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Practice Advice on
CORE
INVESTIGATIVE
DOCTRINE
Second Edition
This has been published as an interim product due to the development
of Authorised Professional Practice (APP) and may be published in an
alternative format in the future as part of the APP programme. 
This version has been released for training purposes only and will 
form part of the APP remit in due course.

2012
Produced on behalf of the Association of Chief Police Officers
by the National Policing Improvement Agency


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Practice Advice on Core Investigative Doctrine, Second Edition
This practice advice contains information to assist policing in the
United Kingdom. It is NOT PROTECTIVELY MARKED under the
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This practice advice has been produced by the National Policing
Improvement Agency (NPIA) on behalf of the Association of Chief Police
Officers (ACPO). It will be updated according to legislative and policy
changes and re-released as required.
The NPIA was established by the Police and Justice Act 2006. As part of
its remit the NPIA is required to develop policing doctrine, including
practice advice, in consultation with ACPO, the Home Office and the
Police Service. Practice advice produced by the NPIA should be used by
chief officers to shape police responses to ensure that the general public
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Practice Advice on
CORE
INVESTIGATIVE
DOCTRINE
Second Edition
2012
Produced on behalf of the Association of Chief Police Officers
by the National Policing Improvement Agency


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Practice Advice on Core Investigative Doctrine, Second Edition
First published 2005
National Centre for Policing Excellence (NCPE)/Centrex
This edition published 2012
National Policing Improvement Agency
10-18 Victoria Street
London SW1H 0NN
The National Policing Improvement Agency (NPIA) is committed to making
a valuable contribution to improving public safety. ACPO and the NPIA
would like to express their thanks to all those involved in the drafting of this
document. All of the responses during the consultation phase of this project
were appreciated and contributed to the final document.
© NPIA (National Policing Improvement Agency) 2012
© ACPO (Association of Chief Police Officers) 2012
All rights reserved. No part of this publication may be reproduced, modified,
amended, stored in any retrieval system or transmitted, in any form or by
any means, without the prior written permission of the National Policing
Improvement Agency and the Association of Chief Police Officers or their
duly authorised representative.
The above restrictions do not apply to Police Service authorities, which are
authorised to use this material for official, non profit-making purposes.
For copyright specific enquiries, please telephone the National Police Library
on 01256 602650.
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Practice Advice on Core Investigative Doctrine, Second Edition
Contents
Preface
5
PART ONE
7
1 Introduction
9
2 Investigative Knowledge
19
3  The Legal Framework
33
PART TWO
57
4  The Criminal Investigation Process
59
5  Investigative Decision Making
79
6 Investigative Strategies
107
7 Management
163
Appendix 1  Glossary
177
Appendix 2
References and Suggested Further Reading

193
Appendix 3
Briefing Models – IIMARC and SAFCOM

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The performance of the police in the area of investigation is
Preface
continually under scrutiny by the government, the criminal justice
system and the media. There is widespread recognition within the
Police Service that there is a need to improve the professionalism of
the investigative response.
Professionalising the Investigation Programme (PIP) was introduced
by the ACPO Crime Business Area as a key initiative within the police
reform agenda. The purpose is to significantly improve the personal,
functional and organisational ability of the Police Service to
investigate crime of any category.
Core Investigative Doctrine provides definitive national guidance
for all investigators as defined by PIP on the key principles of
criminal investigation, irrespective of the nature or complexity of
the investigation. It will assist the Police Service to meet the
challenging targets set by the government, to increase the number
of offenders brought to justice and to improve public confidence in
the investigative process.
By drawing on the collective experience of police practitioners,
stakeholders, academics and current literature, all the principles
which underpin investigation have been compiled into a single,
definitive document for the Police Service. It outlines the legislative
and structural changes which have altered the role of the investigator
to that of the impartial gatherer of material which will be used by all
parties within the criminal justice system.
In order to be effective, the investigator must develop the ability to
make reliable and accountable decisions. This may often be under
pressure or in difficult circumstances. There are many factors which
affect an investigator’s ability to make decisions. A number of
measures, including the investigative mindset and investigative and
evidential evaluation, are proposed in this document which will assist
investigators in making accountable decisions and minimise the
chance of errors.
This practice advice is a strategic overview of the investigative
process, providing a framework for investigative good practice. Its
purpose is to provide investigators with the skills and knowledge they
require to conduct investigations in a competent manner, inspiring
confidence in the investigator and the wider criminal justice system.
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Practice Advice on Core Investigative Doctrine, Second Edition
PART ONE
1 Introduction
9
2 Investigative Knowledge
19
3  The Legal Framework
33
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Practice Advice on Core Investigative Doctrine, Second Edition
Introduction
An investigation is an effective search for material 
to bring an offender to justice. This practice advice
focuses on the knowledge and skills required to
conduct an effective investigation, and is structured
in two parts to assist the reader. Part One includes the
underlying principles and knowledge that support the
process of investigation. Part Two focuses on the
process of investigation. This section defines the
purpose of a criminal investigation and the role of the
investigator. It also demonstrates where investigation
can link to other policing activities and the wider
criminal justice system.

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1: Introduction
Contents
1.1
Outline
11
1.2
Criminal Investigation
12
1.3
Developments in Criminal Investigation
13
1.4
The Role of the Investigator
14
1.5
The Forensic Investigator
14
1.6
The Benefits of Investigation
15
1.7
The Purpose of Core Investigative Doctrine
17
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1: Introduction
This practice advice has been developed by experienced police
1.1 Outline
practitioners with the assistance of the Home Office, the Crown
Prosecution Service (CPS) and academics. It provides definitive
national guidance on the key principles of criminal investigation
which are based on the collective experience of the Police Service
and literature on the process of criminal investigation.
It applies to all levels of criminal investigation including both the
reactive and proactive methods of investigation. It also supports 
the Professionalising Investigation Programme (PIP) and provides 
an outline of the skills required by investigators at Levels 1 to 3.
Professionalising Investigation Programme (PIP) was an
ACPO Crime Business Area lead project commissioned by the
Home Office working in partnership with the NPIA and Skills 
for Justice. Although it was completed in March 2009, it is still
ongoing within the remit of the ACPO Crime Business Area for
Standards, Training and Competence. The programme was
established to improve the professional competence of all
police officers and staff whose roles involve them in conducting
or managing investigations. The programme identified the key
learning and development programmes for investigators in new
or specialist roles who conduct investigations or interviews. It
also identified standards of competence in investigation and
interviewing, which are now established within a suite of
National Occupational Standards (NOS). The standards reflect
the knowledge, understanding and skills which an investigator
must demonstrate through assessment in the workplace.
Workplace assessment is a common feature at all PIP Levels 
of investigator. It is part of the development process to ensure
that investigators can demonstrate the practical application 
of their knowledge and skills and to evidence and maintain
competent performance. Crucially, the national learning
programmes reflect the knowledge, practice advice and
decision-making skills outlined in this document and the NOS.
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1: Introduction
Investigative Level
Example of Role
Typical Investigative Activity
Level 1
Patrol Constable/Police
The initial investigation of crime
Staff/Supervisors.
allegations at the reporting stage and
completing investigations of volume
crime.
Level 2
Dedicated Investigators, eg, CID
Substantive investigation into more
Officer.
serious and complex offences.
Specialist Investigative
Child abuse and safeguarding children,
Substantive investigation in areas which
Roles
family liaison, financial investigation.
require additional specialist investigative
knowledge and skills.
Level 3
Senior Investigating Officer (SIO).
Lead investigator in cases of murder,
stranger rape, kidnap or crimes of
complexity. Category A, B-C.
Level 4
Senior Investigating Officer/Officer in
Critical, complex, protracted and/or
Overall Command.
linked serious crime Category A+.
The Criminal Procedure and Investigations Act 1996 (CPIA) Code of
1.2 Criminal
Practice under Part II of the Act defines a criminal investigation as:
Investigation
An investigation conducted by police officers with a
view to it being ascertained whether a person should be
charged with an offence, or whether a person charged
with an offence is guilty of it. This will include:
• Investigations into crimes that have been committed; 
• Investigations whose purpose is to ascertain whether a
crime has been committed, with a view to the possible
institution of criminal proceedings; and 
• Investigations which begin in the belief that a crime may
be committed, for example, when the police keep premises
or individuals under observation for a period of time, with a
view to the possible institution of criminal proceedings.
While the definition refers specifically to criminal investigations, the
principles set out in this document will apply equally to other types 
of investigations, eg, road traffic matters, anti-social behaviour,
professional standards enquiries or investigations conducted on
behalf of Her Majesty’s Coroner.
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1: Introduction
In 1829 the ‘New Police’ (Maguire, 2003) was established with the
1.3 Developments
purpose of maintaining public order, providing street patrols and
in Criminal
preventing crime. It was not until 1842 that the Metropolitan Police
Investigation
Service formed a small detective branch and adopted an
investigative approach to crime. This change of emphasis was seen
as a radical departure from the traditional role of the patrolling
constable. The detection of crime prior to this had mainly been
conducted by ‘thief-takers’ whose methods were frequently crude
and financially motivated. The new branch provided a more
disciplined approach and by 1878 a Criminal Investigation
Department (CID) served the whole of London. This system quickly
became established as an effective tool in crime control and within 
a short period each force had formed its own CID.
During the twentieth century, two separate and distinct methods 
of investigation developed within the Police Service. Generalist 
CID and uniformed officers employed a reactive method of
investigation which was intended to respond to reported crime. 
In addition, specialist squads, ie, serious crime squads and drug
squads, were set up to deal with organised or invisible crime. 
This used proactive methods of investigation which were largely
intelligence led. Occasionally, major crimes such as homicide or
serious sexual assaults required a greater concentration of
resources than those available locally, resulting in ad hoc major
enquiry teams being brought together. Again, these generally used
a reactive method of investigation, but employed proactive
methods when the circumstances called for them. In broad terms
the two methods of investigation are similar. They are discussed
further in 4.3 The Methods of Criminal Investigation.
Crimes occur under many different circumstances, and the behaviour
of key figures such as victims and offenders cannot always be
predicted. For these reasons individual investigations will vary
considerably. As offenders become more sophisticated, so
investigators develop their skills. Today the Police Service has at its
disposal a wide range of technical and scientific expertise to assist in
the investigation of crime, but it is still incumbent on investigators to
approach all investigations in a structured and methodical manner
as outlined in this practice advice.
Through increased media coverage of crime and criminal behaviour,
and because of the effect that crime can have on individuals and the
local community, the process of criminal investigation has attracted
considerable attention. In addition, there has been an increasing
drive throughout the public sector to improve accountability,
efficiency and effectiveness.
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1: Introduction
Two Royal Commission Inquiries in the 1980s, followed by an Audit
Commission Report in 1994 identified a number of shortcomings in
police investigation. These criticisms included:
• Lack of transparency and accountability; 
• Ineffectiveness in ‘catching’ criminals;
• Miscarriages of justice;
• Abuse of power, corruption and perversion of criminal justice; 
• Erosion of civil liberties and breaches of human rights. 
Handbook of Policing (2003) 
These findings led to a perception that public confidence in the
competence and integrity of the Police Service had declined. The
response to this was the introduction of legislation such as the Police
and Criminal Evidence Act 1984 (PACE), the Criminal Procedure and
Investigations Act 1996 (CPIA), and the Regulation of Investigatory
Powers Act 2000 (RIPA). These changes now provide some statutory
regulation to the conduct of investigations.
The CPIA Code of Practice under Part II of the Act clearly defines
1.4 The Role of
who an investigator is and what their role is within an investigation. 
the Investigator
An investigator is any police officer involved in the conduct
of a criminal investigation. All investigators have a
responsibility for carrying out the duties imposed on them
under this code, including in particular recording information,
and retaining records of information and other material.
The term investigator is, however, not solely applicable to police
officers. Investigations can be conducted by persons other than
police officers with investigative duties, eg, staff from the Serious
Fraud Office (SFO), Independent Police Complaints Commission
(IPCC), Department for Trade and Industry (DTI) or the Department
for Transport (DfT). Section 38 of the Police Reform Act 2002 allows
chief officers to designate police staff as investigating officers.
The introduction of the legislation outlined in 1.3 Developments in
1.5 The Forensic
Criminal Investigation has led to significant changes in the way
Investigator
investigations are carried out.
Traditionally, the police had an adversarial role within the criminal
justice system. They were responsible for recording and investigating
criminal offences, identifying the offender, determining the charges
to be brought and presenting the case in court. 
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1: Introduction
The introduction of the Crown Prosecution Service (CPS) in 1986
removed the police’s authority to act as prosecutor, and more
recently the Criminal Justice Act 2003 (Charging Standards) has
placed responsibility on the CPS to determine the charges which can
be brought against an offender (in all but exceptional circumstances)
see 3.6.3 Charging Standards.
The introduction of PACE in 1984 regulated the actions of the
investigator and made provision to safeguard offenders’ rights and
to improve the quality of material available to courts. The CPIA has
now made the methods of investigation accountable to the criminal
justice system. It requires investigators to capture all available
material of value to the prosecution or the defence, and preserve it
for possible disclosure. Investigators have a duty to record, retain and
reveal material that is relevant to the criminal investigation. RIPA has
further expanded the obligation on investigators to justify and
account for their actions. As a result of these changes, the
investigator's role has become more inquisitorial than adversarial. 
The similarity between the roles of the investigator and the forensic
scientist can be described as follows: 
Traditionally forensic evidence has always relied upon
proving continuity to rebut any possible argument of
contamination or interference. In a very real way this
regime is now an imperative for all evidence… The real
test for policing will be our ability to provide investigators
of such credibility that they resemble in every respect the
best forensic scientists. 
Sir David Phillips in Ede and Shepherd (2000) 
Although investigation forms a large part of the core business
1.6 The Benefits
function of the Police Service, it should not be considered in isolation
of Investigation
from other policing activity.
The Government is committed to reducing crime and responding to
local community concerns. In 2010, as part of the Structural Reform
Plan, the Coalition Government established the following priorities:
• Enable the police and local communities to tackle crime and
anti-social behaviour; 
• Increase the accountability of the police to the communities 
they serve; 
• Secure borders and control immigration;
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1: Introduction
• Protect people’s freedom and civil liberties;
• Protect people from terrorism.
The National Intelligence Model (NIM) is a business process which
drives policing in the UK. It requires the input of accurate and timely
information into force intelligence systems, much of which is
generated by investigations. The analysis of this information assists
in identifying crime patterns and trends, crime hot spots and series
links. This information can then be used to brief and deploy patrols
and identify intelligence-led initiatives designed to reassure
communities and reduce offending and anti-social behaviour.
Investigations inevitably require direct contact between a member
of the public and the investigator. The point of contact and
effectiveness of investigators will have a substantial impact on the
quality of material provided by victims and witnesses. It will also
encourage their cooperation and help their understanding of the
criminal justice process.
Where individuals have been the victims of crime or have witnessed 
a traumatic event, they expect the Police Service to provide security,
support and reassurance, in addition to an effective investigation.
By building this relationship, the investigator is able to keep victims
and witnesses informed, and impart valuable information about the
variety of resources available, eg, Victim Support, crime reduction
advice and reparation schemes. In serious or traumatic investigations
it may be necessary to establish a rapport through a third party in
order to preserve the investigator’s objectivity, and to avoid them
becoming an advocate of the victim or their family. Third parties
may include a family liaison officer (FLO), sexual offence liaison
officer (SOLO), local authority or charitable victim support scheme.
Every investigation provides the individual investigator and the 
Police Service with a unique opportunity to recognise and understand
the impact of crime and criminality upon the community. This
knowledge can be used in a variety of ways to settle local priorities,
eg, to guide preventive policing patrols, to promote and disseminate
crime prevention advice and to provide reassurance to specific
vulnerable individuals, groups or locations within communities.
Investigators engaged with suspects also have an opportunity to
obtain material relating to crime and criminality in the local and
wider community which can be used to improve personal and
organisational knowledge through the provision of intelligence. 
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1: Introduction
This will assist in reducing crime and the fear of crime in the
community, and will encourage positive intervention with offenders
to prevent or reduce recidivism.
Neighbourhood Policing Teams
Neighbourhood policing teams are a valuable asset in
investigations. Local teams play a crucial role in building
community trust and confidence in the Police Service. 
The neighbourhood officers (which include police community
support officers) are in direct contact with the community and
have developed a good understanding of its issues. This
knowledge can be used to investigate many crimes, and in
particular any crime which might be considered a local priority. 
Neighbourhood policing is part of the mainstream policing
activity and is managed through NIM. More detailed
information can be found at
http://www.neighbourhoodpolicing.co.uk
This practice advice gives definitive national guidance on the key
1.7 The Purpose of
principles of criminal investigation. This will provide:
Core Investigative
Doctrine

• A conceptual framework for all subsequent doctrine developed
for the Police Service; 
• A way of promoting good practice among practitioners; 
• A research agenda by identifying investigative areas where little
or no definitive guidance currently exists; 
• A way of identifying the skills and knowledge required by
practitioners, which are reflected in NOS and PIP. 
The practice advice provides a high-level overview of the process of
criminal investigation. Crimes, however, vary in terms of the
motivation of those committing them, the response of victims and
witnesses and the amount of material that is available for
investigators to collect. A great deal of guidance has been produced
by ACPO and the Home Office to assist investigators in specific cases,
and this is referred to where relevant in the text. Irrespective of the
differences between cases, the application of the principles of this
practice advice will enable investigators to make logical, structured
and accountable decisions, despite the circumstances in which those
decisions are made.
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1: Introduction
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Investigative
Knowledge
This section outlines the knowledge that investigators
require in order to conduct a competent criminal
investigation. Investigative knowledge enables
investigators to determine if a given set of
circumstances amounts to a criminal offence, to
identify the types of material that may have been
generated during the commission of an offence and
where this material may be found. It also ensures that
investigations are carried out in a manner which
complies with the rules of evidence, thereby increasing
the likelihood that the material gathered will be
admitted as evidence.

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2: Investigative Knowledge
Contents
2.1
Knowledge Required by Investigators 
21
2.2
The Legal Framework
21
2.2.1 Ethics
23
2.3
The Characteristics of Crime
25
2.3.1 Modus Operandi (MO)
25
2.3.2 Characteristics of Victims, Witnesses
and Offenders
26
2.4
National and Local Force Policies
27
2.5
Investigative Principles
28
2.6
Developing Knowledge
30
2.7
Summary
31
Figures
Figure 1 The Relationship between Knowledge and Experience 30
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2: Investigative Knowledge
Knowledge assists investigators to make effective and accountable
2.1 Knowledge
decisions during an investigation. It enables them to locate, gather
Required by
and use the maximum amount of material generated by the
Investigators
commission of an offence to identify and bring offenders to justice.
There are four areas of investigative knowledge required to conduct
an effective investigation. These are: 
• The Legal Framework; 
• Characteristics of Crime; 
• National and Local Force Policies; 
• Investigative Skills. 
All investigators must have a current and in-depth knowledge of
2.2 The Legal
criminal law and the legislation which regulates the process of
Framework
investigation. For those investigators working at PIP Level 1 
(see 1.1 Outline) opportunities to locate and gather material will
frequently occur while they are carrying out routine policing activities
such as responding to incidents or interviewing victims and witnesses.
To make full use of these opportunities, investigators must make,
without access to legal textbooks or other sources of advice, 
on-the-spot decisions on which is the most appropriate course of
action to take. For these reasons it is essential that all investigators,
including those at PIP Level 1, should understand the following:
• Legal definitions of offences likely to be encountered; 
• Points that have to be proved; 
• Potential defences available from statute and case law; 
• Powers that support and regulate the investigation process; 
• Relevant rules of evidence.
Without this knowledge investigators could take action that is
unlawful, or gather material in such a way as to make it unlikely that
it will be accepted as evidence in court. For further details of the legal
framework for criminal investigations, see 3 The Legal Framework. 
Those carrying out investigations at PIP Levels 2 and 3, and those
in specialist investigation units should already have a thorough
knowledge of criminal law. Their roles may also require them to
provide advice and support to PIP Level 1 investigators. PIP Level 2
and 3 investigators are likely to be carrying their own caseload of
investigations, commonly involving serious or complex offences.
These types of crime are often committed by experienced
offenders who may try to prevent material from being gathered.
Maintaining a current knowledge of criminal law will assist
investigators to deploy the full range of investigative techniques
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2: Investigative Knowledge
that can help to overcome this and ensure that investigations are
able to withstand the high level of scrutiny applied to them by the
criminal justice system.
Legal knowledge developed over time enables investigators to
anticipate the types of defence that may be put forward by a
suspect. This anticipation allows investigators to gather additional
material which will enable courts to test the validity of the defence.
A common feature of serious and major crime enquiries is the high
volume of material that they generate and the complex chains of
evidence which result. To successfully manage this material,
investigators require an in-depth working knowledge of the criminal
law and in particular the CPIA.
Investigators acquire legal knowledge through formal training
courses and from experience of conducting investigations. Formal
training courses include the Initial Police Learning and
Development Programme (IPLDP) or the Initial Crime Investigators
Development Programme (ICIDP). Investigators can use the NCALT
MLE platforms to develop or acquire new knowledge. The legal
framework within which investigators work changes frequently and
they should, therefore, ensure that they maintain a current
knowledge of the law, including new legislation and amendments
to existing law.
Sources of legal knowledge available to investigators include:
• Home Office Circulars; 
• Force orders; 
• The media; 
• Legal digests;
• http://www.legislation.gov.uk (legislation/statutory
instruments);
• Police journals; 
• Force crime training departments; 
• Conferences and seminars; 
• Daily or extended briefings within the force;
• Legal databases (eg, Police National Legal Database (PNLD)
and Lawtel).
See also Appendix 2.
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2: Investigative Knowledge
2.2.1 Ethics
Investigators have access to a range of legal powers that enable
them to conduct effective investigations. Under certain conditions,
these powers allow investigators to deprive individuals of their liberty,
to use reasonable physical force, to enter their homes or other private
premises, to gain access to private information and to deploy
intrusive surveillance techniques. They also have a high level of
discretion in how they choose to use these powers.
These legal powers and the discretion with which they can be used
place a responsibility on investigators to use both of them ethically.
The Statement of Mission and Values (ACPO 2011) provides basic
ethical principles which should guide investigators.
The mission of the police is to make communities safer 
by upholding the law fairly and firmly; preventing crime 
and antisocial behaviour; keeping the peace; protecting 
and reassuring communities; investigating crime and 
bringing offenders to justice.
We will act with integrity, compassion, courtesy and 
patience, showing neither fear nor favour in what we do. 
We will be sensitive to the needs and dignity of victims 
and demonstrate respect for the human rights of all.
We will use discretion, professional judgement and 
common sense to guide us and will be accountable for 
our decisions and actions. We will respond to well-founded 
criticism with a willingness to learn and change.
We will work with communities and partners, listening 
to their views, building their trust and confidence, making 
every effort to understand and meet their needs.
We will not be distracted from our mission through fear 
of being criticised. In identifying and managing risk, 
we will seek to achieve successful outcomes and to 
reduce the risk of harm to individuals and communities.
In the face of violence we will be professional, calm 
and restrained and will apply only that force which is 
necessary to accomplish our lawful duty.
Our commitment is to deliver a service that we and 
those we serve can be proud of and which keeps our 
communities safe.
In addition, there are a number of principles which are widely
accepted within the Police Service. These principles are underpinned
by the recognition that policing works best where it has the support
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and cooperation of the community. The Police Service enjoys a high
level of support but this can be undermined in specific instances and
among specific communities if they lose confidence in either the
effectiveness of the police or the way in which police powers are
exercised. The following principles are designed to ensure that
investigations are conducted in ways which are ethical and
encourage community support:
• When a crime is reported, or it is suspected that one may 
have been committed, investigators should conduct an 
effective investigation;
• The exercise of legal powers should not be oppressive and
should be proportionate to the crime under investigation; 
• As far as operationally practical and having due regard to an
individual’s right to confidentiality, investigations should be
carried out as transparently as possible, in particular, victims,
witnesses and suspects should be kept updated with
developments in the case;
• Investigators should take all reasonable steps to understand 
the particular needs of individuals including their age, culture,
religious and other beliefs, ethnic origin, sexual orientation,
disability, lifestyle, sex or age;
• Investigators should have particular regard for vulnerable adults
and children;
• Investigators should respect the professional ethics of others.
This is particularly important when working with those whose
role it is to support suspects.
Conducting ethical investigations will ensure that individuals and
communities have confidence in the effectiveness of the Police
Service and the fairness of the processes and techniques they use.
This will make it more likely that victims and witnesses will provide
investigators with material and that they will cooperate in the
prosecution of offenders. Winning the broad support of communities
also helps to cultivate sources of intelligence for the future.
Investigators should remember that offenders are members of
communities and can influence others about the police. They may
also themselves become victims and witnesses. If they believe that
they have been treated ethically during an investigation, they are less
likely to form and communicate a negative view of the police to
others. They are also more likely to cooperate with investigations in
the future, whether as a victim, witness or suspect.
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Crime can be placed into three broad categories: property crime,
2.3 The
crimes against the person and crimes against society (sometimes
Characteristics
known as victimless crimes). An examination of the types of crime
of Crime
in each category shows that they vary widely in terms of the
behaviours involved, the types of victims, the motives of offenders,
the methods used to commit the crime and the degree of planning
involved. The differences between crimes are significant for
investigators because the circumstances in which crimes are
committed determine the volume and distribution of the material
available for them to gather. For example, although shoplifting and
commercial fraud are both property crimes, they generate quite
different types of material because of the different ways in which
these offences are committed.
The wide range of criminal behaviour, the circumstances in which it
can occur and the numerous ways in which victims, witnesses and
offenders are likely to behave, means that investigators can be faced
with numerous sources which may produce material. Making
appropriate decisions in these circumstances requires knowledge 
of some of the factors involved. These factors include the modus
operandi (MO) of offenders and the characteristics of victims,
witnesses or offenders.
2.3.1 Modus Operandi (MO)
A detailed knowledge of the MOs employed by offenders within their
policing areas will enable investigators to:
• Understand how a particular crime has been committed, the
type of material that may have been generated in the
commission of the offence and how or where this material might
be recovered.
• Identify linked series of crimes committed with the same MO.
(Pooling material from a linked series of crimes is often a highly
effective way of progressing an investigation.)
• Identify links between crimes and known offenders who use the
same MO.
• Predict future offending patterns, which may enable preventive
or protective measures to be taken.
• Predict future offending patterns, which may enable offenders 
to be caught red-handed.
• Identify likely disposal routes and markets for stolen or illicit
property, eg, drugs.
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2.3.2 Characteristics of Victims, Witnesses and Offenders 
Investigators must understand the ways in which victims, witnesses
and offenders are likely to respond when a crime is committed
and how best to obtain material from them. This will require
knowledge of:
• The range of communities in their local area (community
includes occupational groups, social groups and others who may
meet infrequently due to a shared interest or a shared use of an
area or facility);
• The language, cultural and/or social needs or disability issues of
victims, witnesses and offenders (bearing in mind the duty to
provide reasonable adjustments) which may be relevant when
investigating crime; 
• Persistent and problematic offenders within the area and their
networks of associates who may also be involved in their criminal
behaviour, eg, the disposal of stolen goods; 
• Potential intelligence sources, both overt and covert, eg,
Homewatch, and Covert Human Intelligence Sources (CHIS),
that are available within a community and are capable of
providing material which may assist in an investigation. 
Investigators can develop knowledge of MOs and the characteristics
of victims, witnesses or offenders from reading the literature on
criminal investigation (see Appendix 2), by studying national and
local intelligence briefings and examining individual intelligence and
crime reports.
Sources on the characteristics of crime include:
• Colleagues and supervisors; 
• Experts (eg, Crime Scene Investigators (CSI), fingerprint
experts, forensic scientists, forensic psychologists, Police
Search Advisers (PolSA)); 
• Crime and criminal intelligence databases (local, force, national);
• Other databases (eg, Police Online Knowledge Area (POLKA),
Serious Crime Analysis Section (SCAS)); 
• The local and national media; 
• Police journals; 
• Home Office Science, Research and Statistics documents; 
• Seminars; 
• Briefings; 
• Internal reviews; 
• The National Police Library, Bramshill. 
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2: Investigative Knowledge
The Police Service is a complex organisation with a wide strategic
2.4 National and
remit. In order to manage the range of tasks it is required to perform,
Local Force Policies
the Police Service and its partners develop policies at both a national
and local level.
The reasons for producing policy include: 
• Ensuring compliance with the law; 
• Procedural good practice; 
• Improving customer service; 
• Resource management; 
• Managing inter-agency cooperation. 
Many of these policies have a direct bearing on the conduct of
investigations, and investigators should have knowledge of those
that are relevant to the type of investigations they are involved in. 
Such knowledge enables investigators to comply with legislation,
follow procedural good practice and gain access to the most
appropriate resources or level of inter-agency cooperation required
to successfully conclude an investigation. They will also be better
equipped to meet the needs of individual victims and the
wider community.
At a national level, policy is developed by the Home Office and ACPO.
The policies produced are usually mandatory, but in some cases they
are subject to local variation. Local variation arises because of the
differences between force structures, their configuration of resources
and the individual needs of their local communities. Local policy may
be developed at the force or Basic Command Unit (BCU) level and
may be subject to more frequent change than national policy as a
consequence of local changes in the policing environment. 
The application of national and local policy will vary considerably
between forces and, therefore, investigators should refer to their local
force for further specific guidance in this area. 
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Examples of national policy include: 
• National Intelligence Model (NIM); 
• National Investigative Interviewing Strategy; 
• Code of Practice on Police Use of Firearms and Less Lethal
Weapons.
Local force policies are publicised in a number of formats 
which include:
• Force orders; 
• Electronic or verbal briefings; 
• Force intranet systems; 
• Force newspapers. 
The areas of knowledge outlined in this subsection are essential for
2.5 Investigative
every investigator. However, investigators will be ill-equipped to
Principles
locate, gather and use the material generated in the commission of 
a crime to bring an offender to justice without a thorough knowledge
of key investigative principles set out in sections 4 to of this
practice advice.
The principles an investigator must have in order to conduct an
effective investigation include: 
• An overview of the investigative process and planning required
to conduct an investigation; 
• Decision making and how it can be improved by the application
of the investigative mindset; 
• Investigative and evidential evaluation which can assist the
investigator to determine the value of material gathered during
the investigation; 
• Core investigative strategies common to most investigations
including victim and witness, suspect and scene strategies; 
• Management issues common to all investigations. 
Investigations should be conducted with integrity, common sense
and sound judgement. Actions taken during an investigation 
should be proportionate to the crime under investigation and take
account of local cultural and social sensitivities. The success of 
an investigation relies on the goodwill and cooperation of victims,
witnesses and the community. Heavy-handed, discriminatory 
or disproportionate actions risk losing that cooperation. Effective
investigators should maintain a balance between conducting an
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objective investigation and maintaining an approach which
recognises the concerns of all the parties involved. 
Where routine investigative actions have failed to gather sufficient
material, investigators should explore alternative methods. Creative
thinking may be required to determine the most appropriate type of
action that will progress an investigation, but this does not mean
that the high legal standards and integrity expected of investigators
will be compromised. Investigators should be open to the ideas and
experiences of others. Colleagues and supervisors are a readily
available source of investigative information and investigators
should consult them when trying to identify the most appropriate
action to take in any given case. Most forces have various specialist
investigation units, such as intelligence or covert policing teams,
which are a valuable source of information about specific types of
investigation techniques. 
Creative thinking requires the investigator to look at the
problem in another way, to question any assumptions that may
have been made and to query the validity of all information.
Investigators must continually question whether there may be
another possible explanation for the material gathered. 
It is becoming increasingly common to use technology to investigate
crime. Although investigators cannot be expected to know the detail
of scientific principles underlying technology such as DNA testing,
behavioural profiling and fingerprinting, they should be familiar with
the ways in which these techniques can contribute to the material
that is gathered during an investigation. This knowledge can be
acquired through formal courses and by questioning the experts that
they work with, eg, CSIs or Forensic Medical Examiners (FMEs). 
Investigators should never hesitate to question what they are told by
experts. If an investigator does not understand the material or how it
might be interpreted then it is highly likely that others will have the
same difficulty. It is part of the investigator’s role to anticipate this
and to find explanations that can be easily understood by everyone.
If an investigator has any reason to doubt the validity of material
supplied by experts, he or she should ask for guidance from
supervisors or the crown prosecutor on the appropriate course of
action to take.
The NPIA Specialist Operations Centre holds a database of 
experts who may be able to provide guidance and assistance in 
an investigation.
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2: Investigative Knowledge
Although investigators can acquire knowledge from formal training
2.6 Developing
courses and the literature that exists on criminal investigation, they
Knowledge
also need practical experience of investigations to underpin this
knowledge. However, investigators should never rely on experience
alone. This is because experience is unique to the individual, people
learn at different speeds and each will learn something different
from the process. There may also be a lack of exposure to certain
types of crime and criminality so that investigators will not be
experienced in some areas. Moreover, while every investigation
provides a new opportunity to increase the individual’s investigative
experience, it is a time-consuming way of building up knowledge.
Ideally, investigators should have a combination of formal training
and experience. In practice, however, the balance between the two
will vary between individual investigators because of differing
opportunities to attend formal training courses, their access to the
literature and the experience that they are able to acquire.
The relationship between taught knowledge and experience is
demonstrated in Figure 1.
Figure 1 – The Relationship between Knowledge and Experience
Knowledge
HIGH
LIMITED
gained via
CONSIDERABLE
EXTENSIVE
Has in-depth
education,
Occasional
Professional use
knowledge but
training
in-depth use
in many
has not used
and
of skills
applications
it often
learning
K
N
O
LIMITED
MEDIUM
CONSIDERABLE
W
Has some
Occasional use
Regular use
L
knowledge but
in several
in several
E
has not used
applications
applications
Experience
D
it often
gained
G
through
E
exposure
LIMITED
LIMITED
such as
Occasional use
Regular use
NONE
learnt on
in specific 
in specific
the job
applications
applications
LOW
LOW
EXPERIENCE
HIGH
Typical ‘Theoretical’ Route
Skill = Knowledge + Experience
Typical ‘Practical’ Route
Skill = Experience + Knowledge
Stewart (1998)
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2: Investigative Knowledge
It is likely that new entrants will start their police careers with little or
no knowledge or experience of criminal investigation. New entrants
are trained through the IPLDP. The Student Officer Learning and
Assessment Portfolio (SOLAP) records their progress regarding NOS
and the Qualifications and Credit Framework (QCF) units of the
Diploma in Policing (the new qualification for IPLDP). Police Action
Checklists (PACs) are used to assess the performance of student
officers in a number of real situations before the officer can move 
to independent patrol. By attending courses and gaining practical
experience, their knowledge will develop further. The established
Personal Development Review (PDR) system provides individuals 
and the organisation with the facility to identify areas for future
development. The process model outlined in 4.4 A Model of the
Investigation Process 
can also be used as a tool for supervisors in
managing staff performance regarding investigation. Those with
limited experience of investigations should be encouraged to
accompany experienced colleagues on current investigations,
or to consider alternative developmental methods such as
secondment or mentoring.
Investigators will acquire knowledge from a number of different
sources and in different ways. Torrington and Hall (1995) found 
that in order to be an effective investigator, the individual must be
interested in investigation and acquire a habit of gathering
knowledge. They must also have the desire and the skills to learn.
If the investigator is not interested or motivated, they will not
understand the principles of investigation and, significantly, they
will not understand how to link theory to practical application during
an investigation.
Investigators should be encouraged to identify and share good
2.7 Summary
practice with colleagues both at local force level and nationally. 
It is only by doing this that the Police Service as a whole can learn
from the collective experience of its investigators.
The National Policing Improvement Agency acts as a central point
of contact for the Police Service to capture and promote emerging
good practice.
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The Legal
Framework
This section outlines the legal framework within which
all investigations, from the simple to the complex,
should be grounded.

Its purpose is to provide a brief overview of certain
overarching Acts and how they link to investigations.
It also explains other important legal issues such as the
Public Interest test and emphasises the necessity of
gathering credible, reliable, relevant, and ultimately
admissible evidence.

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3: The Legal Framework
Contents
3.1
Evidence
35
3.2
Best Evidence
36
3.2.1 Circumstantial Evidence
37
3.3
The Adversarial System
38
3.4
Police and Criminal Evidence Act 1984
40
3.5
Prosecution of Offences Act 1985
41
3.6
The Code for Crown Prosecutors
41
3.6.1 The Evidential Test
42
3.6.2 The Public Interest Test for Prosecutions
42
3.6.3 Charging Standards
44
3.7
Criminal Procedure and Investigations Act 1996
46
3.8
The Human Rights Act 1998
48
3.9
Youth Justice and Criminal Evidence Act 1999 (YJCEA) 49
3.10 Regulation of Investigatory Powers Act 2000
52
3.10.1 Interception of Communications
52
3.10.2 Surveillance and Covert Human Intelligence
Sources (Part II)
53
3.10.3 Electronic Data Protected by Encryption
(Part III)
54
3.10.4 Police Act 1997
54
3.11 Equality Act 2010
54
3.12 Duty of Care
55
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3: The Legal Framework
In terms of the law of evidence, all evidence which is sufficiently
3.1 Evidence
relevant to the facts in issue is admissible, subject to the exclusionary
rules. Consequently, all evidence that is irrelevant should be excluded.
The test of relevance is:
…evidence which makes the matter which requires proof
more or less probable.
Lord Simon of Glaisdale in DPP v Kilbourne [1973]
AC 729, p 756 
The ‘facts in issue’ are those facts which the prosecution must prove
in order to establish the guilt of a defendant. The standard of proof
in the criminal courts is proof beyond reasonable doubt.
Just as there is evidence on behalf of the prosectution so
there may be evidence on behalf of the prisoner which
may cause a doubt as to his guilt. In either case he is
entitled to the benefit of the doubt. But while the
prosecution must prove the guit of the prisoner, there is 
no such burden laid on the prisoner to prove his innocence
and it is sufficient for him to raise a doubt as to his guilt; 
he is not bound to satisfy the jury of his innocence.
Viscount Sankey L.C. in the judgement in 
Woolmington v OPP [1935] AC 462
The court will decide on the admissibility of the evidence, but
generally evidence will be ruled inadmissible if:
• It is hearsay and does not fall within the categories specified in
section 114 Criminal Justice Act 2003 which permit the
admission of such evidence; 
• It is the opinion of a non expert; 
• It is withheld as a matter of public policy; 
• The witness is incompetent to give such evidence on the basis
that they do not understand the questions put and are unable 
to give understandable answers (section 53 – Youth Justice and
Criminal Evidence Act 1999); 
• It is a confession which does not meet the admissibility
requirements of section 76 PACE; 
• The evidence falls within the provisions of section 78 PACE. 
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Section 78
PACE Exclusion of Unfair Evidence
Section 78(1) In any proceedings the court may refuse to allow
evidence on which the prosecution proposes to
rely to be given if it appears to the court that,
having regard to all the circumstances, including
the circumstances in which the evidence was
obtained, the admission of the evidence would
have such an adverse effect on the fairness of the
proceedings that the court ought not to admit it. 
Section 78(2) Nothing in this section shall prejudice any rule of
law requiring a court to exclude evidence. 
Section 78(3) This section shall not apply in the case of
proceedings before a magistrates’ court inquiring
into an offence as examining justices.
Evidence of Bad Character 
Previously, evidence of bad character fell within the category of
inadmissible evidence, however, this has been changed by the
Criminal Justice Act 2003 (CJA). For further information on bad
character, see 6.11.10 Suspect Interviews and ACPO (2008)
Practice Advice on Evidence of Bad Character, 
Second Edition.
The CJA represents a marked overhaul of the criminal justice system
and is the response to widespread calls for reforms to modernise and
rebalance the system in favour of victims and witnesses, as well as to
restore public confidence. For other significant amendments brought
about by this Act, see 3.6.3 Charging Standards and 3.7 Criminal
Procedure and Investigations Act 1996.

Best evidence derives from a 1745 judgment where the court held
3.2 Best Evidence
that it is the ‘best [evidence] that the nature of the case will admit’
(Omychund v Barker). It has come to mean primary evidence or 
‘first-hand evidence’ (eye witnesses or the original document). 
Secondary evidence will be admitted, however, under certain conditions.
In the decision of Garton v Hunter (1969), Lord Denning stated:
Nowadays we do not confine ourselves to the best
evidence. We admit all relevant evidence. The goodness or
badness of it goes only to weight and not to admissibility.
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The jury will be advised to attach more weight to the evidence of
primary sources and this is accordingly the best evidence and
that which the investigator should strive to find. It is the duty of an
investigator to look for all relevant information and to place before
the court all best evidence uncovered, irrespective of which side
it supports.
Historically, courts assumed that best evidence is the recollection of
what the witness saw or heard. As a trial may be many months after
the event, it is questionable if this is still the best evidence.
Technological advances mean that best evidence may now be one 
or other kind of recording of what might have been seen or heard.
Evidence captured in this way can have considerable advantages in
respect of suspect interviews, significant witnesses and others. For
further information see 6.5 Victim and Witness Strategy and
ACPO (2004) Practical Guide to Investigative Interviewing.
An investigator should strive to ‘set the scene’ for the court and jury.
Accordingly, any relevant evidence about the circumstances
surrounding the commission of the crime should be sought as it can
usually be presented to the court.
3.2.1 Circumstantial Evidence 
This evidence can be defined as evidence of the circumstances
surrounding the offence or event from which a fact in issue may be
inferred. This form of evidence is especially relevant in situations
when crimes are committed and there are no witnesses present. 
A few common examples of situations when circumstantial evidence
would be relevant are: 
• Where a person is found in possession of recently stolen goods
and offers no explanation or offers one that is deemed to be
false, then the jury may infer that he or she stole or dishonestly
handled the goods, depending on the circumstances; 
• When fingerprints are found at the scene of a crime, in the
absence of an innocent explanation to account for the prints,
the jury can infer the identity of the offender; 
• When inferences from silence are sought in terms of the Criminal
Justice and Public Order Act 1994. 
There is a perception that this evidence is weaker than direct evidence,
however, the statement of Lord Hewart CJ in the decision of Taylor,
Weaver and Donovan [1928] 21 Cr App R20 should be remembered:
‘It is no derogation of evidence to say that it is circumstantial.’
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Continental systems of justice are usually termed ‘inquisitorial’.
3.3 The Adversarial
The court operates as a tribunal investigating the circumstances of
System
the crime and strives to find the truth. All parties connected with the
investigation are examined, the evidence and its evaluation are
accumulated in an open file, and eventually a determination is
made by the court.
The ‘adversarial’ system is different in concept. The court sits in
independent arbitration between the prosecution and the defence.
The prosecution makes an allegation and brings evidence to support
their case. The defence are only obliged to respond once a prima
facie case has been made, and can argue at any stage that the
prosecution have not made out a sufficient case against them.
The court acts as an umpire requiring both sides to observe the rules
of the contest. In only very limited circumstances can it call evidence
of its own volition. In most serious cases the court is assisted by jurors
whose job it is to assess the evidence presented to them and then
determine guilt or innocence. If the jury find the prosecution has
proved its case, the court will determine sentence.
While discovery of the truth is hopefully a by-product of a trial, it is not
its central purpose. The central purpose is to establish whether, within
the rules, the prosecution can prove their case beyond reasonable doubt.
Protagonists for the adversarial system argue that the testing of
witnesses by skilled advocates in cross-examination is on balance the
best way to provide a jury with convincing grounds for their
determination. They believe that the process of adversarial advocacy 
in the hands of skilled professionals is the best and fairest way of testing
the real worth of evidence. In Mechanical and General Inventions
Co Ltd v Austin 
[1935] AC 346, page 359, the House of Lords stated: 
Cross-examination is a powerful and valuable weapon for
the purpose of testing the veracity of a witness and the
accuracy and completeness of his story.
There has been much concern, for example in rape cases, that victims
and witnesses are unfairly disadvantaged in this process. It has been
argued that vigorous cross-examination of witnesses, often without
access to any original notes, many months after the event, perhaps
distressed and almost certainly in a state of apprehension by virtue
of the process, is not the fairest way to obtain evidence. For these
reasons there has been a general easing of conditions in favour of
witnesses as follows:
• Special measures can be used for vulnerable and intimidated
witnesses, see 3.9 Youth Justice and Criminal Evidence Act 1999;
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• Prior to going into the witness box witnesses may refresh their
memory from a statement or note made at a time reasonably
close to the events in issue; 
• Section 139 CJA allows for witnesses to refresh their memory,
while giving evidence, from a document made or verified by
them, subject to the specified requirements;
• In terms of the Code of Conduct for the Bar, barristers have a
duty to guard against asking questions, in cross-examination,
which are only intended to insult or annoy the witness or some
other person.
For further information see
http://www.justice.gov.uk/publications/statistics-and-
data/criminal-justice/criminal-justice-statistics.htm

The adversarial system of justice obliges each side to observe
common rules of advocacy but places a different requirement on
them in terms of how they conduct their case. The prosecution has
to observe a public interest standard in their conduct which entails
acting fairly towards the defence at every stage. This means they
should only advance evidence they believe to be true and at the
least must disclose anything injurious to their case. They are
obliged to make available anything which will assist the defence.
On the other hand the defence are not obliged to assist the
prosecution in any way. Their task is not to prove the innocence 
of the defendant, but to do everything they can to undermine the
prosecution case. They are not obliged to disclose evidence
injurious to their case and they can lead any evidence, whatever 
its credibility, provided they do not know it to be false. This very
different standard flows from the nature of the adversarial system
– the defendant only being obliged to answer the case against
them if it has been made out satisfactorily.
The partisan character of defence advocacy as against the public
interest standard for the prosecution is a logical feature of the
adversarial system. The Law Society advises its members in the
following terms at paragraph 2.2 of the The Law Society (2003)
Law Society’s Code for Advocacy:

Advocates have an overriding duty to the court to ensure
in the public interest that the proper and efficient
administration of justice is achieved: they must assist the
court in the administration of justice and must not deceive
or knowingly or recklessly mislead the court.
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It goes on to state at paragraph 2.3 (a) Advocates:
...must promote and protect fearlessly and by all proper
and lawful means the clients’ best interests and do so
without regard to their own interests or to any
consequences to themselves or to any other person.
Lord Justice Auld’s major review of the criminal justice process
observed that the distinction between the inquisitorial and adversarial
systems is no longer clear. European Convention on Human Rights
(ECHR), Article 6 and its attendant jurisprudence in holding that an
accused cannot be obliged to give evidence against him or herself
affords greater protection to defendants in the inquisitorial system.
The development of pre-trial hearings and arrangements about
defence disclosure are moderating the adversarial system. In effect,
this amounts to more judicial management of cases.
The Police and Criminal Evidence Act 1984 (PACE) and its Codes of
3.4 Police and
Practice are key elements of the framework of legislation, providing
Criminal Evidence
the police with the powers they need to investigate crime. In doing
Act 1984
so, PACE sets out to strike the right balance between the powers of
the police and the rights and freedoms of the public. Maintaining
that balance is a key part of PACE.
The Act sets out the working practices applicable to the investigation
of crime, which are enshrined by the principles of fairness and
openness. It covers areas such as search, detention in custody,
interviewing, and an array of police powers, many of which will
feature in every investigation. The PACE Codes of Practice explain
how the principles should be interpreted in practice.
PACE was based on the recommendations in the report Modern
Records Centre (1981) Royal Commission on Criminal
Procedure, 
a body which had been directed in its terms of reference
to strike a balance between the interests of the community and the
rights and liberties of the individual suspect. PACE has been
amended many times since then.
Breaches of PACE are not a matter for remedy in the course of a trial,
but can lead to police disciplinary proceedings or can form the basis
of a complaint or legal action against the police. While breaches of
PACE or its Code of Practice will not automatically lead to evidence
being excluded, PACE does provide the court with the discretion to
exclude prosection evidence where admitting it would have an
adverse effect on the fairness of the proceedings. This discretion is
likely to be used where there have been significant and substantial
breaches of PACE, as in R V Hassan [2004] EWCA crim 1478.
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The need for a single prosecuting authority in England and Wales
3.5 Prosecution of
was raised in the report of the 1981 Royal Commission. In response
Offences Act 1985
the Prosecution of Offences Act 1985 was promulgated. This Act
created the Crown Prosecution Service (CPS), under the directorship
of the Director of Public Prosecutions (DPP), which has the
responsibility for public prosecutions in England and Wales. The
Service incorporated all existing police prosecution departments
under the DPP, thereby removing the authority for the police to
conduct public prosecutions.
The Act provides the statutory framework within which the CPS
operates and the authority for various administrative functions. 
It also gives the CPS the power to decide whether to prosecute; 
see 3.6 The Code for Crown Prosecutors.
It is important that the police work with the CPS using the
Prosecution Team Approach. In the course of an investigation they
should remember the role and duties of the prosecutor.
The prosecution team ethos means a joint approach by both the
police and the CPS to improve performance and bring more
offenders to justice.
Part II of the Prosecution of Offences Act relates to the awarding of
costs in criminal matters. Part III concerns the issue of time limits for
the completion of preliminary stages of proceedings and the period
defendants may be remanded in custody awaiting trial.
Amendments have been brought about by the Crime and Disorder
Act 1998 to reduce the delays in the criminal justice system. These
include a suspension of the time limits where the defendant
absconds and flexibility to allow for different time limits depending
on the type of case.
Under section 10 of the Prosecution of Offences Act 1985, the DPP is
3.6 The Code for
required to issue The Code for Crown Prosecutors. A revised version
Crown Prosecutors
was issued in 2010. This document details the basic principles to be
followed in making case decisions, ie, whether to prosecute. It also
sets out that a prosecutor’s duty is to be fair, independent and
objective, not to be affected by improper pressure and not to let their
view of a case be influenced by considerations of ethnic or national
origin, age, sex, religious or political beliefs, or the sexual orientation
of the offender, victim or witness.
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The majority of the document deals with the tests to be employed in
a decision to prosecute, namely the evidential test and the Public
Interest test for prosecutions.
3.6.1 The Evidential Test
This is the first stage of the decision-making process. The prosecutor
must be satisfied that there is enough evidence to provide a realistic
prospect of conviction against the defendant(s) on each of the
charges preferred. This is an objective test so the code directs that
the criteria for satisfying the test should be that:
…an objective, impartial and reasonable jury or bench of
magistrates or judge hearing a case alone, properly
directed and acted in accordance with law, is more likely
than not to convict the defendant of the charge alleged.
The Code for Crown Prosecutors (2010)
In making this assessment the prosecutor must have regard to the
possible defence case.
Crucial to this test is the consideration of whether the evidence can
be used in court and whether it is reliable. This involves considering
issues of admissibility and any reasons why the evidence may be
ruled unreliable. For further information see
http://www.cps.gov.uk/publications/code_for_crown_prosecutor
s/codetest.html

Only once this test has been satisfied must thought be given to the
Public Interest test.
3.6.2 The Public Interest Test for Prosecutions
The classic statement on public interest, which was made by Lord
Shawcross, has been supported by Attorney Generals ever since: 
It has never been the rule in this country – I hope it never
will be – that suspected criminal offences must
automatically be the subject of prosecution.
The public interest must be considered in each case where there is
enough evidence to provide a realistic prospect of conviction.
A prosecution will usually take place unless there are public interest
factors tending against prosecution which clearly outweigh those
tending in favour. Although there may be public interest factors
against prosecution in a particular case, the prosecution will often go
ahead and those factors will be put to the court for consideration in
mitigation when sentence is being passed.
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Crown prosecutors must balance factors for and against prosecution
carefully and fairly. Public interest factors that can affect the decision
to prosecute usually depend on the seriousness of the offence or the
circumstances of the suspect. Some factors may increase the need to
prosecute but others may suggest that another course of action
would be better. Deciding on the public interest is not simply a
matter of adding up the number of factors on each side, crown
prosecutors must decide how important each factor is in the
circumstances of every case and then make an overall assessment.
Each case is unique and must be considered on its own facts and
merits. However, there are general principles that apply to the way 
in which crown prosecutors must approach every case. There are
many factors which could be significant, eg, the likelihood of a
nominal penalty being handed down at court, the defendant has put
right their misdeeds, national security could be harmed. The
consequences for the victim are always considered.
Cases involving youths are usually only referred to the CPS for
prosecution if the youth has already received a reprimand and final
warning, unless the offence is so serious that neither of these are
appropriate. Reprimands and final warnings are intended to prevent
reoffending and the fact that a further offence has occurred
indicates that attempts to divert the youth from the court system
have not been effective. The public interest will usually require a
prosecution in such cases, unless there are clear public interest
factors against prosecution.
Only once both tests have been satisfied will a prosecution be instituted.
Where it is intended to keep the suspect in custody after charge and
the evidence required to satisfy the aforementioned tests is not
available, the crown prosecutor must apply the ‘Threshold Test’.
In applying the test a number of factors must be considered.
In connection with the first part of the Threshold Test:
• There must be at least reasonable suspicion the the person 
charged has committed the offence;
• They must consider the evidence currently available; 
• The evidence is relevant, able to put into an admissible format
for presentation in court, and would be used in the case.
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If this is satisfied, the prosecutor should progress to the second part
of the Threshold Test.
5.9    …the prosecutor must be satisfied that there are reasonable
grounds for believing that the continuing investigation will
provide further evidence, within a reasonable period of time,
so that all the evidence taken together is capable of
establishing a realistic prospect of conviction in accordance
with the Full Code Test.
5.10 The further evidence must be identifiable and not merely
speculative.
5.11 In reaching a decision under this second part of the
Threshold Test, the prosecutor must consider:
a)
the nature, extent and admissibility of any likely further
evidence and the impact it will have on the case;
b)
the charges that all the evidence will support;
c)
the reasons why the evidence is not already available;
d)
the time required to obtain the further evidence and
whether any consequential delay is reasonable in all 
the circumstances.
5.12 If both parts of the Threshold Test are satisfied, prosecutors
must apply the public interest stage of the Full Code Test
based on the information available at that time.
CPS (2010) The Code for Crown Prosecutors
If the test is satisfied the person will be charged, although the
prosecutor must subsequently review the evidence in terms of the
code tests to determine whether the matter should proceed.
CPS (2010) The Code for Crown Prosecutors also deals with
modes of trial, accepting a guilty plea, restarting a prosecution and
charging, the latter having been radically transformed by the CJA.
3.6.3 Charging Standards
Section 6 of CPS (2010) The Code for Crown Prosecutors deals
with charges and advises that the charges preferred should:
• Reflect the seriousness of the offending;
• Give the court adequate sentencing powers as well as powers 
to impose appropriate post-conviction orders;
• Enable the case to be presented in a clear and simple way.
Previously a custody officer would make a decision on whether there
was sufficient evidence to charge and would thereafter charge the
person or release them without charge, unless the matter was still
under investigation. The CJA has amended section 37 PACE to allow
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the CPS to play a greater role in the charging process. CPS (2011)
The Director’s Guidance on Charging: Guidance to Police
Officers and Crown Prosecutors, 
Fourth Edition (referred to
hereafter as Guidance on Charging) issued by the DPP, under
section 37A of PACE states in paragraph 19 and 20:
Prosecutors will make charging decisions in all Indictable
Only cases, any either way offence not suitable for
sentence in a magistrates’ court or not anticipated as a
guilty plea, and the offences specified in the proviso above. 
In a case where any offences under consideration for
charging by the police include any offence which must be
referred to a prosectutor under this Guidance then all
offences in the case will be referred to a prosecutor to
consider which should be charged.
Section 37(7a) now includes the provision for a person to be released
without charge and on bail, with or without conditions, to enable the
DPP to make a decision on whether to charge. It allows the
authorisation of police detention while the decision to charge is
taken. The custody officer can determine whether to charge under
the offences specified in the guidance document although both the
decision to prosecute and the charges to be preferred will be subject
to review by a crown prosecutor.
In making a decision on whether to charge, the custody officer must
have regard to the tests set out in CPS (2010) The Code for Crown
Prosecutors. 
If there is insufficient evidence to meet the required tests
and it is not appropriate for the person to be released on bail after
charge, the custody officer must assess the case against the Threshold
Test. If this test is satisfied then the person shall be charged and placed
before the court for a ruling on pre-trial custody. After a reasonable
time, which will depend on the circumstances of the case, the crown
prosecutor must review the evidence in terms of the test in CPS (2010)
The Code for Crown Prosecutors 
and make a decision on whether to
proceed or not. In line with the CPS (2005) Disclosure Manual,
paragraph 4.1, custody officers can consult prosecutors if they intend
to detain in order to apply to court for a remand in custody.
In all other matters crown prosecutors have the responsibility for
deciding whether to charge. Investigating officers are directed to
seek an early consultation with the duty prosecutor 
to identify issues such as the required lines of enquiry, evidential
requirements and pre-charge procedures. In terms of Guidance on
Charging, 
an investigating officer is required to place certain
information before the prosecutor so that the latter can make the
necessary decisions on charging. The information to be supplied is
detailed in Guidance on Charging, paragraph 7.2.
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A summary of the roles and responsibilities of the custody officer in
relation to the statutory charging provisions is set out in Guidance
on Charging, 
section 8.
The Criminal Procedure and Investigations Act 1996 (CPIA) applies 
3.7 Criminal
to all criminal prosecutions that began after 31 March 1997.
Procedure and
Investigations

Part 5 of the Criminal Justice Act 2003 (CJA) substantially changed 
Part 1 of the CPIA by increasing the obligations of the prosecution 
Act 1996
to disclose documents and by increasing substantially the range of
matters that the defence must disclose.
The CPIA provides a legal definition of a criminal investigation and
requires a Code of Practice to be put in place covering the conduct of
investigations. It also places an obligation on the investigator to
provide the defence and the court with a fair appraisal of what the
investigation uncovered. This makes the conduct of the investigation
a relevant issue in the trial, for example, if the enquiry is found not to
be objective and reasonable.
The CPIA sets the standard for the conduct of criminal investigations
and the recording and disclosure of evidence. Not only must the
enquiry be fair, it must also be recorded so that any evidential material
gathered can be made available to all sides.
The Act is divided into seven parts, but the first two are of the main
importance to the Police Service. 
• Part I sets out the procedure for disclosure and the consequences
of failing to comply.
• Part II defines ‘Criminal Investigation’ and the effects of the Code
of Practice issued under the Act. This includes the duties of the
Police Service with regard to disclosure.
The Act is supplemented by the Code of Practice issued under Part II. 
The Crown Prosecution Service (2005) Attorney General
Guidelines on the Disclosure of Information in Criminal
Proceedings 
(hereafter referred to as Attorney General Guidelines
on Disclosure
) and Crown Prosecution Service (2004) Joint
Operational Instructions Disclosure of Unused Material 
are also
of importance. For further information see
http://www.attorneygeneral.gov.uk/Publications/Pages/Attorne
yGeneralsGuidelines.aspx 
and
http://www.cps.gov.uk/legal/d_to_g/disclosure_manual/
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In terms of Part I of the Act, the prosecution have a duty to disclose any
information which might reasonably be considered capable of either
undermining the prosecution case or assisting the defence case. The
original primary and secondary disclosure by the prosecution have been
removed and replaced with a single continuing objective test.
Despite the fact that the Act places a duty to disclose on the prosecutor,
the Code of Practice states that the police have a responsibility to assist
in the process. (This issue is also covered by Attorney General
Guidelines on Disclosure.
)
Investigators and disclosure officers must be fair and
objective and must work together with prosecutors to
ensure that disclosure obligations are met. A failure to take
action leading to inadequate disclosure may result in a
wrongful conviction. It may alternatively lead to a
successful abuse of process argument, an acquittal against
the weight of the evidence or the appellate courts may
find that a conviction is unsafe and quash it.
Attorney General Guidelines on Disclosure, paragraph 23
The defence are expected to provide a detailed statement setting out
the nature of their defence, including any particular defence upon
which they intend to rely and any points of law they wish to raise. 
A list of defence witnesses must also be supplied to the prosecution. 
Part II sets out the duties of the police in relation to criminal
investigations, including disclosure. The Code of Practice under Part II
defines the roles of the officer in charge of the case, the disclosure
officer, the investigator and the supervisor of the aforementioned
officers. It also sets out the duties and responsibilities of the officers
regarding the recording and retention of material obtained in the
course of a criminal investigation.
The CPIA Code of Practice (issued under Part II of the Act) defines
the role of a disclosure officer as 
…the person responsible for examining material retained
by the police during the investigation; revealing material to
the prosecutor during the investigation and any criminal
proceedings resulting from it, and certifying that he has
done this; and disclosing material to the accused at the
request of the prosecutor.
Under section 6C of the CPIA, the defence are required to notify 
the court and the prosecution if they intend to call witnesses at trial.
Section 21A of the CPIA provides that a code of practice must be
issued to set out guidance that police officers and other persons
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charged with investigating offences must follow if they arrange or
conduct interviews of proposed witnesses whose details are disclosed
to the prosecution by a defendant. The full title of the code is the Code
of Practice for Arranging and Conducting Interviews of Witnesses
Notified by the Accused. It came into force on 1st May 2010.
The Human Rights Act 1998 (HRA) applies to all public authorities. 
3.8 The Human
It makes it unlawful for public bodies like the police to violate the rights
Rights Act 1998
contained in the ECHR which have been listed in the Act. These are
Articles 2 to 12 and 14 to 18 of the ECHR, plus Articles 1 to 3 of the
First Protocol and Article 1 of the Thirteenth Protocol to the Convention.
Article 2
Right to Life
Article 3
Prohibition of Torture
Article 4
Prohibition of Slavery and Forced Labour
Article 5
Right to Liberty and Security
Article 6
Right to a Fair Trial
Article 7
No Punishment Without Law
Article 8
Right to Respect for Private and Family Life
Article 9
Freedom of Thought, Conscience and Religion
Article 10 Freedom of Expression
Article 11 Freedom of Assembly and Association
Article 12 Right to Marry
Article 14 Prohibition of Discrimination
For further information see
http://www.legislation.gov.uk/ukpga/1998/42/contents
Where there has been a breach of the ECHR – or even where there 
is about to be – the victim can take proceedings in court under the
HRA. They may be able to take judicial review proceedings, obtain 
an injunction to stop the violation, force the public authority to take
action or obtain damages and compensation.
Any person who is a victim of a violation can use the HRA. A victim
includes anyone directly affected by the actions, or inactions, of any
public body. A victim may include an applicant who has not yet
suffered the consequences of an alleged breach of the Convention
by a public authority, provided there is a real threat of their being
affected by it in the future. For example, a person who is likely to be
subject to surveillance by the police as part of an investigation will be
able to use the HRA even though they have not yet had their privacy
interfered with. However, a person who is no more affected than any
other member of the public is unlikely to be able to use the Act.
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The HRA principally affects investigations by providing a set of
standards which must be met in order to permit interference in the
rights of privacy of an individual. For an official body such as the
police to enquire into the affairs of a citizen they must be able to
show that their activities:
• Are in accordance with the law;
• Are necessary in a democratic society in pursuit of one or more
legitimate aims specified in Article (2) ECHR;
• Are proportionate to the aim pursued.
These principles can be expanded into the following, which should
underpin all investigations:
• That there were reasonable grounds to suspect some knowledge
or involvement relevant to the criminal offending or disturbance
of the peace;
• That the proper procedures have been followed, recorded and all
actions were authorised;
• That the nature of the interference is proportional to the matter
being investigated in its seriousness;
• All the options were considered and all the relevant factors recorded;
• That the methods used are necessary for the purpose of the enquiry.
Part II of this Act deals with vulnerable and intimidated witnesses
3.9 Youth Justice
and is of particular importance to an investigator. The Act has
and Criminal
identified categories of persons who are to be considered as vulnerable
Evidence Act 1999
or intimidated witnesses and, accordingly, may be afforded special
measures during an investigation and at any court appearances.
(YJCEA)
Section 16 covers witnesses who are eligible because of age (under 
18 years) or incapacity, and section 17 covers witnesses who are eligible
on grounds of fear or distress about testifying. For further information
see http://www.justice.gov.uk/guidance/docs/achieving-best-
evidence-criminal-proceedings.pdf

Some witnesses fall into the vulnerable or intimidated witness
categories automatically, so are eligible for special measures.
Vulnerable witnesses are those:
• Under 18 years of age (as mentioned above);
• Who have a mental disorder;
• Who have a significant impairment of intelligence and 
social functioning;
• Who have a physical disability or who suffer from a physical disorder.
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Intimidated witnesses are defined by section 17 of the Act as those
whose quality of evidence is likely to be diminished by reason of fear
or distress. In determining whether a witness falls into this category,
the court should take account of:
• The nature and alleged circumstances of the offence;
• The age of the witness;
and where relevant:
• The social and cultural background and ethnic origins of the witness;
• The domestic and employment circumstances of the witness;
• Any religious beliefs or political opinions of the witness;
• Any behaviour towards the witness by the accused;
• Members of the accused person’s family or associates;
• Any other person who is likely to be either an accused person 
or a witness in the proceedings.
Complainants who are witnesses in respect of a sexual offence,
murder or violent crimes such gun or knife crime are classed as
intimidated. They are eligible for assistance in relation to those
proceedings unless the witness has informed the court of their wish
not be eligible.
In addition, witnesses who might be regarded as intimidated include:
• Victims and witnesses in cases that involve
– domestic violence
– racially motivated crime
– crime motivated by reasons relating to religion
– crime motivated by reasons related to disability
– homophobic and transphobic crime
– gang-related violence;
• Victims and witnesses who have experienced past or repeat
harassment or bullying;
• Victims and witnesses who are elderly and frail.
Other types of witness eligibility for special measures depend on the
existence of additional factors.
Special Measures
In 2011 the Coroners and Justice Act 2009 introduced amendments
to the YJCEA special measures provisions. These amendments:
• Raise the upper age limit of child witnesses automatically
eligible for special measures from those under 17 to include
those under 18; 
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• Provide child witnesses with more choice and flexibility about
how they give their evidence; 
• Make specific provision for a supporter to the witness to be
present in the live-link room; 
• Extend the automatic eligibility for special measures to witnesses
in certain gun or knife crimes; 
• Make special provision for the admissibility of video-recorded
evidence in chief of adult complainants in sexual offence cases
in the crown court.
The special measures available (under the YJCEA 1999) to vulnerable
and intimidated witnesses with the agreement of the court include:
• The use of screens (section 23); 
• The use of live TV link (section 24) ;
• Giving evidence in private (section 25) (limited to sexual
offences and those involving intimidation);
• The removal of wigs and gowns (section 26);
• The use of video-recorded interviews as evidence-in-chief
(section 27).
Vulnerable witnesses are also eligible for the following special measures:
• Communication through intermediaries (section 29);
• The use of special communication aids (section 30).
An application for special measures to be invoked can be made by the
prosecution or defence, or they can be ordered by the court based on
its observations. Whether or not special measures are allowable or
whether any evidence coming from them is admissible is a matter for
the court. The problem for the investigator is that the use of special
measures has to be anticipated beforehand. To retain the integrity of
the case the investigator, during the course of investigations, must be
aware of any witness or defendant who may require special
measures, and take the appropriate steps when obtaining evidence.
The potential witness must be given enough information to allow
them to decide whether they require special measures.
For further information and guidance see
http://www.justice.gov.uk/guidance/docs/achieving-best-
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Prior to this Act, covert police investigations were governed on a
3.10 Regulation of
non-statutory basis by Home Office guidance which mirrored the
Investigatory
authorisation process contained within the Interception of
Powers Act 2000
Communications Act 1985. Following a series of landmark
judgments handed down by the European Court of Human Rights, 
it was made clear that a non-statutory authorisation regime in
respect of these techniques was insufficient. To ensure compliance
with the ECHR, RIPA was introduced to provide a statutory
framework for the use of covert techniques. RIPA seeks to ensure
that any interference with an individual’s rights under Article 8 is
necessary, lawful and proportionate. Law enforcement agencies
must show their actions are necessary in pursuit of one or more
legititmate aims set out in Article 8(2) ECHR, including those:
• Which are in the interests of national security;
• Relating to preventing or detecting crime (or in certain cases
serious crime);
• Linked with safeguarding the economic wellbeing of the UK.
The Act is made up of five parts:
• Part I relates to the interception of communications and the
acquisition and disclosure of communications data; 
• Part II covers the use of surveillance, Covert Human Intelligence
Sources (CHIS) and undercover officers; 
• Part III deals with the investigation of electronic data protected
by encryption;
• Part IV is the authority for independent judicial oversight of the
powers in the Act; 
• Part V relates to miscellaneous and supplemental matters.
3.10.1 Interception of Communications 
Part I of the Act provides a ‘warrantry regime’ for the interception 
of postal and telephone communications in the course of their
transmission. Section 5(3) of the Act sets out the grounds on which
an interception warrant may be granted. In order for a warrant to be
granted, section 5(2) must also be complied with; the Secretary of
State must believe that the conduct authorised is proportionate to
what is sought to be achieved.
Part I of the Act also sets out the circumstances where such an
interception may take place without the need for a warrant, for example,
where both of the parties to the communication have consented.
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3.10.2 Surveillance and Covert Human Intelligence
Sources (Part II) 

Surveillance activity and CHIS conduct will, if properly authorised
under Part II of RIPA, be lawful for all purposes. There are codes of
practice which give guidance on the procedures to use when
undertaking surveillance, interference with a property and using 
a CHIS. These are available at
http://www.homeoffice.gov.uk/counter-terrorism/regulation-
investigatory-powers/ripa-codes-of-practice/

Intrusive surveillance 
Section 26(3) defines this as covert surveillance that is carried out
in relation to anything taking place on any residential premises or
in any private vehicle and involves the presence of an individual on
the premises or in the vehicle, or is carried out by means of a
surveillance device.
Covert surveillance is not intrusive where it is carried out by means of
a surveillance device not present on the residential premises or in the
private vehicle, unless it consistently provides information of the
same quality and detail as might be expected from a device which is
actually present on the premises or in the vehicle. 
Section 32 sets out the persons responsible for the authorisation of
intrusive surveillance, together with the grounds upon which such
authorisations may be granted. 
Directed surveillance 
Section 26(2) defines directed surveillance as covert surveillance 
that is undertaken for the purposes of a specific investigation or
operation, and in such a manner as is likely to result in obtaining
private information about a person. The person about whom private
information is likely to be obtained need not be a person specifically
identified for the purposes of the investigation or operation 
(section 26(2)(b)).
Section 28 sets out the persons responsible for the authorisation 
of directed surveillance, together with the grounds upon which such
authorisations may be granted. If the surveillance is intrusive it
cannot be directed surveillance.
Surveillance is not directed if it is in immediate response to events
and circumstances where it would not be reasonably practicable to
obtain an authorisation.
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Covert Human Intelligence Source 
Section 26(8) defines a CHIS as a person who establishes or
maintains a personal or other relationship with a person for the
covert purpose of using that relationship to obtain information, 
to provide access to any information or to disclose information
obtained as a consequence of that relationship.
Section 29 sets out the persons responsible for the authorisation 
for CHIS, together with the grounds upon which such authorisations
may be granted.
3.10.3 Electronic Data Protected by Encryption (Part III) 
Section 49 empowers the police to issue a notice requiring disclosure
of the decryption key to any protected information which has lawfully
come into their possession. All matters involving the decoding of
encrypted matter should be referred to the National Technical
Assistance Centre (NTAC).
3.10.4 Police Act 1997
By their nature, covert investigations often involve entry onto private
land or interference with privately owned property. In the absence of
any lawful authority such actions can constitute a civil wrong,
actionable by the owner of the property or land for damages. The
effect of section 92 of the Police Act 1997 is that no entry on or
interference with property or with wireless telegraphy shall be
unlawful if properly authorised under that Act. 
The authorisation process and the grounds upon which such an
authorisation may be granted are set out at section 93 of the Act. 
The Equality Act 2010 legislates against unfair treatment, and
3.11 Equality Act
promotes equal opportunities, both at work and in society in general.
2010
It also applies to the treatment of people providing goods, facilities
and services, and those exercising public functions.
There have been a number of Acts which sought to achieve this, but the
Equality Act 2010 replaces these with a single Act. It simplifies legislation
in the area, and reduces the opportunities for conflict and inconsistencies.
The Act specifies nine protected characteristics which cannot be used
as a justification to treat someone unfairly. Everyone has one or
more of the protected characteristics, so the Act protects everyone
against unfair treatment. The protected characteristics are:
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• Age;
• Disability;
• Gender reassignment;
• Marriage and civil partnership;
• Pregnancy and maternity;
• Race;
• Religion or belief;
• Sex;
• Sexual orientation.
Note: Different protected characteristics have different levels of
protection; for example, pregnancy and maternity are not protected
in relation to harassment, and age protection in public functions is
only given to those aged 18 and over.
Section 29 applies specifically in relation to the provision of services
and outlines that a ‘service provider’ must not discriminate, harass or
victimise a person to whom the service is being provided. The Police
Service, in the exercise of public functions, must not, therefore,
conduct itself in a way that constitutes discrimination, harassment or
victimisation. Furthermore, the service provider is required to make a
reasonable adjustment for a disabled person.
Regulations relating to the Act came into effect in September 2011.
They require each public authority listed in the Schedules to the
Regulations to publish information to demonstrate compliance with
the duty imposed by section 149 (1) of the Act. Section 149 places a
duty on public authorities, including the police, to have due regard to
the need to eliminate discrimination, harassment and victimisation
when carrying out their functions. They should advance equality of
opportunity, and foster good relations between people whether they
share a relevant protected characteristic or not.
For further information see
http://homeoffice.gov.uk/equalities/equality-act/
The Statement of Mission and Values (ACPO 2011) is the Police
3.12 Duty of Care
Service’s high level declaration of how members will protect and serve
the public. Among other things, the Statement requires a constable to
uphold the law fairly and firmly, and to act with integrity, compassion,
courtesy and patience. For further information see 2.2.1 Ethics.
Article 2 ECHR imposes a positive obligation on police to act to
safeguard the lives of those within their jurisdiction. Unless special
circumstances exist, however, common law states that the police do
not owe a duty of care to protect individuals from harm caused to
them by criminals.
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A crucial case relating to this obligation was Osman v UK (1998) 29
EHRR, which states that the positive duty in Article 2 to safeguard life
will have been violated when the authorities knew or ought to have
known at the time of the existence of a real and immediate risk to
the life of an identified individual or individuals from the criminal acts
of a third party and that they failed to take measures within the
scope of their powers which, judged reasonably, might have been
expected to avoid that risk.
In addition, there are other significant pieces of legislation which involve
a duty of care such as the Health and Safety at Work Act etc.1974, the
Corporate Manslaughter and Corporate Homicide Act 2007, plus other
areas of law such as tort law (specifically in relation to negligence).
Courts have also held that in certain circumstances the police have a
duty to take all reasonable steps to protect potential victims from a
real and immediate threat to their lives arising from:
i Actual or threatened criminal acts of another;
ii Suicide Karen Orange v Chief Constable West Yorkshire Police
[2001] EWCA Civ 611.
The Osman ruling has since been reinforced by the ruling in 
Van Colle v CC Hertfordshire [2008] UKHL 50.
In Vellino v Chief Constable of the Greater Manchester Police [2001],
the court held that the police had a duty of care for the health and
safety of those in their custody, but that they owed no duty of care
towards an arrested person to ensure that he was not injured in a
foreseeable attempt to escape from lawful custody. 
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PART TWO
4  The Criminal Investigation
Process
59
5  Investigative Decision Making
79
6 Investigative Strategies
107
7 Management
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The Criminal
Investigation
Process
This section defines the term ‘material’ and how it is
generated and used in the criminal investigation
process. It explains how the initial amount of material
generated by an offence can differ from the amount
which is finally admitted as evidence in court. 

Section 4 also describes the criminal investigation
process, which includes reactive and proactive methods
of investigation.

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Contents
4.1
Material
61
4.2
How Material Is Generated
63
4.2.1 The Total Material Generated by an Offence
63
4.2.2 The Material Gathered by the Police
63
4.2.3 The Material that Is Admissible as Evidence
64
4.3
The Methods of Criminal Investigation
66
4.4
A Model of the Investigation Process
66
4.4.1 Instigation
68
4.4.2 Initial Investigation
69
4.4.3 Investigative Evaluation
72
4.4.4 Further Investigation
73
4.4.5 Suspect Management
73
4.4.6 Evidential Evaluation
74
4.4.7 Case Management
74
Checklists
Checklist 1 Suspect Considerations
76
Checklist 2 Victim and Witness Considerations
77
Checklist 3 Investigator’s Considerations
77
Figures
Figure 2 The Attrition of Material During the Investigation Process 63
Figure 3 The Stages of Criminal Investigations
67
Figure 4 Initial Investigation
70
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Understanding what material is, how it is generated during a criminal
4.1 Material
offence and how it can be located, gathered and used are all central
to the investigation of crime. The definition of material used
throughout this document is taken from the CPIA Code of Practice
under Part II of the Act:
Material is material of any kind, including information 
and objects, which is obtained in the course of a criminal
investigation and which may be relevant to the
investigation; ... material may be relevant to an
investigation if it appears to an investigator, or to the
officer in charge of an investigation, or to the disclosure
officer, that it has some bearing on any offence under
investigation or any person being investigated, or on the
surrounding circumstances of the case, unless it is
incapable of having any impact on the case.
It may be difficult for investigators to predict what will or will not 
be relevant to the investigation, particularly during the early stages
when the exact nature of what has happened, and who is involved
may still be unclear. In the first instance, if in doubt, investigators 
are advised to err on the side of caution and, where it is legally
permissible, to gather and retain material. Subsequently, supervisors
or crown prosecutors can be consulted to determine whether the
material should be retained for use in the investigation or in
subsequent court proceedings.
There are a number of potential sources from which the investigator
can gather material. These include: 
• Victims; 
• Witnesses; 
• Suspects; 
• Locations, including scenes of crime and the victim’s or
suspect’s premises;
• Passive data generators, which are systems that collate or record
data automatically and generate material which is not intended
solely for the purpose of an investigation, eg, CCTV recordings,
telephone records, banking and credit card records;
• Intelligence databases.
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Material may present itself in different formats. Any tangible object
could be material. Intangible things such as sound or images can be
reproduced in a format (eg, video or audio recordings) that can
be used in evidence. In practice, the most common formats for
material are:
• Statements; 
• Documents; 
• Reports; 
• Physical exhibits such as weapons, clothing, stolen goods and
biological or chemical material; 
• Fingerprints; 
• Images; 
• Audio or video recordings. 
The skill of the investigator is not only to identify and locate
potential sources of material but also to understand how the
material must be gathered and stored in a format that is
evidentially admissible. 
Information, Intelligence and Evidence
Whether material becomes information, intelligence or evidence
is dependent on the use to which it is put.
For example, a CCTV image of a disturbance can be:
• Information – if it is used to identify the time, location,
circumstances and numbers involved in the incident; 
• Intelligence – if it is analysed together with other material to
identify local people who frequent that area, have similar
clothes and are suspected of involvement in other disturbances;
• Evidence – if it is used in court to show that a particular
suspect was involved in the disturbance.
All material gathered during an investigation is subject to the
CPIA, irrespective of whether it is used as information,
intelligence or evidence.
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Figure 2 illustrates the reduction in the total amount of material
4.2 How Material
generated by a criminal event and the eventual amount that is used
Is Generated
in court. Ideally, the total amount of material generated by a
criminal event will be collected by the police and be admissible as
evidence, but this is rarely possible. 
Figure 2 – The Attrition of Material During the
Investigation Process 

The Total Material Generated by an Offence
The Material Gathered by the Police
The Material
that Is
Admissible as
Evidence
4.2.1 The Total Material Generated by an Offence 
The amount of material that is generated by a criminal event
depends on a number of factors, such as whether the crime is
spontaneous or planned, the offender’s criminal experience, the
number of people who know that the offender is involved and the
level of contact between the offender and the victim. Each crime has
a unique mix of material, but the amount is finite as there are only so
many witnesses or so much physical evidence.
4.2.2 The Material Gathered by the Police 
The aim of the investigator is to maximise the amount of material
that is collected. It is not always possible to collect all of the
material generated by an offence. Some physical material may be
lost or destroyed, some witnesses may not be located, and some of
the material will only be known to offenders who do not reveal it to
others. Starting an investigation as soon as possible after an
offence has been committed will enhance the investigator’s
opportunity to gather the maximum amount of material
(the Golden Hour principle). 
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While it should always be the investigator’s goal to gather material
that will later be admissible as evidence, there will inevitably be
occasions when this cannot be achieved. The rules that determine
what material will be accepted by a court as evidence are complex
and are often themselves contested within a criminal trial. As a
consequence, all material may be judged to be admissible under
certain circumstances. There are a number of general principles,
however, which mean that some material will not normally pass the
evidential test, eg, hearsay, second person testimony, intelligence
reports or evidence of opinion. Even though the material is of a type
that is generally not admissible, it does not mean that it should not
be gathered or that it will not assist the investigation. Such material
may be highly valuable in setting parameters for other investigative
activities or generating lines of enquiry that may produce other
relevant, reliable and admissible material, and should, therefore,
always be gathered. 
4.2.3 The Material that Is Admissible as Evidence 
As an investigation progresses the amount of material that will be
capable of being used as evidence in court will be less than that
gathered by the police. The interpretation of the rules of evidence
are complex and investigators should always provide the CPS with 
all of the material that has been gathered so that decisions can be
made as to its value as evidence. 
Any material (subject to public interest immunity) gathered during
the course of an investigation that is not used as evidence may be
disclosed to the defence as part of the unused material in
the investigation.
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The Golden Hour 
The Golden Hour is a term for the period immediately following
the commission of an offence when material is abundant and
readily available to the police. Positive action in the period
immediately following the report of a crime minimises the
attrition of material and maximises the chance of securing the
material that will be admissible in court. 
The list below outlines some Golden Hour considerations for
investigators.
Victims:
Identify, support and sensitively
preserve evidence;
Scenes:
Identify, preserve, assess and
commence log;
Suspects:
Identify, arrest and preserve;
Witnesses:
Identify, support and prioritise (key
and significant), record first account
and description of suspect(s); 
Log:
Decisions and rationale for them,
circumstances, resources and
conditions;
Family/Community:
Identify, inform, primary support
(needs, concerns expectations,
sensitivity);
Physical Evidence:
Preservation (CCTV, public transport,
escape routes, ambulances, hospitals); 
Intelligence:
Identify, prioritise, maximise, exploit,
consider, community and open source; 
Prevent Contamination: Victims, scenes, witnesses, suspects; 
Lines of Responsibility: Identify, inform, brief, coordinate 
and review. 
The Metropolitan Police Service
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4: The Criminal Investigation Process
There are two methods of criminal investigation – reactive and
4.3 The Methods
proactive. The proactive method is sometimes called intelligence-led
of Criminal
or covert investigation. 
Investigation
The main difference between these two methods is that the reactive
method starts with the discovery of a crime and seeks to bring
offenders to justice by uncovering material that identifies suspects
and provides sufficient evidence to enable a court to determine
their guilt. The technique of reactive investigations focuses on
interviewing victims, witnesses and suspects, the examination of
scenes and the development of forensic links between suspects and
the offence. The proactive method usually starts with an intelligence
analysis that a particular individual or group is involved in criminal
enterprise. This is often organised crime such as drug dealing, fraud
or people trafficking. Individual instances of such offending are
rarely reported to the police and so generally the techniques of
reactive investigation cannot be used. As a result, investigators
generally use a range of covert surveillance techniques which are
designed to link offenders to the criminal enterprise. These
techniques are often complemented by financial investigations 
and forensic science techniques. 
The two methods of investigation may overlap, particularly after 
a suspect has been arrested. A reactive investigation may also use
covert policing techniques as part of the overall strategy and vice
versa. The two methods of investigation should not, therefore, be
considered as being wholly discrete or mutually exclusive. 
The type of activity individual investigators engage in and the 
4.4 A Model of
type of material that is gathered varies depending on whether
the Investigation
investigations use the reactive or proactive method. However, 
Process
they all go through similar stages, as shown in Figure 3.
The dark grey sections represent activities selected from
investigative strategies, see 6 Investigative Strategies, the grey
sections represent the main decision points, see 5 Investigative
Decision Making 
and the whit
e sections are the outcomes that
can be achieved. 
Every investigation is different and may require a different route
through the model. For example, in some cases the identity of the
offender is known from the outset and the investigation quickly
enters the suspect management phase. In others, the identity of 
the offender may never be known or will only be discovered after 
a lengthy further investigation. 
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Figure 3 – The Stages of Criminal Investigations
Instigation
Initial Investigation
No Further Investigation –
Investigative Evaluation
Further
intelligence input to system
Investigation 
Suspect Management
No Charge/
Evidential Evaluation
Further
Other Disposal
Investigation 
Charge
Case Management
Activities
Court
Decisions
Outcomes
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4.4.1 Instigation
The instigation of criminal investigations can occur in a number of ways:
• Reports from the general public such as attendance at police
stations, phone calls, online and to patrol officers; 
• Referral by other agencies; 
• Intelligence links to other crimes (linked series); 
• Reinvestigation as a result of new information, cold case or other
type of review; 
• Discovered as a consequence of other police actions. 
Call takers, public counter staff and patrol officers receiving initial
reports will be guided by force policy on the information that is to 
be gathered and the action that is to be taken in any given case. 
As a general principle, they must be mindful that when receiving
these reports they are commencing an investigation and will receive
material that is relevant to it. They are under the same obligations as
others involved in the investigation to record and retain this material
and to ensure that it is communicated to the investigating officer.
The investigators should be familiar with the investigative strategies
relating to victims and witnesses as this will enable them to exploit
early opportunities to gather material by questioning the person
reporting the crime, see 6 Investigative Strategies. 
The arrangements for receiving reports of crime vary from force
to force and investigators should familiarise themselves with their
local arrangements.
Sources of instigation in proactive investigations are: 
• Crime pattern analysis; 
• Market analysis; 
• Network analysis; 
• Subject analysis; 
• Operational intelligence assessment; 
• Tactical assessment; 
• Criminal business analysis; 
For further information see ACPO (2008) Practice Advice on
Analysis 
and ACPO (2007) Practice Advice: Introduction to
Intelligence-Led Policing.

These sources are often referred to by investigators as intelligence
packages and have been developed by national, force or local
intelligence systems. They identify groups or individuals who are
assessed as being involved in ongoing criminal activity. They will
generally have been through a tasking and coordinating process
which has then allocated them for further investigation. 
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Irrespective of the method of instigation, those involved need to
understand that the instigation phase is part of the investigation 
and is, therefore, subject to the provisions of the CPIA. 
Investigators who are allocated crimes for further investigation need
to identify who dealt with the instigation phase, establish what
decisions have already been made, what actions have been taken
and what material has been gathered so far. They should take
possession of this material, or, if the original material remains in the
hands of third parties, obtain copies and ensure that the original is
retained in accordance with the CPIA. 
4.4.2 Initial Investigation 
Not every report of a crime will require an initial investigation.
Intelligence packages and referrals from other agencies are likely to
be allocated for further investigation without the need for any initial
investigation. The majority of reports are, however, likely to be dealt
with by deploying police officers to a scene or to the person
reporting. In some police forces the initial investigation of certain
categories of crime are dealt with entirely over the telephone before
a decision to carry out further investigation is made. 
Whether carried out in person or over the telephone, the quality of
the initial investigation is a significant factor in gathering material
that leads to detection of a crime. The first opportunity to locate and
gather material may be the only opportunity. For example, scenes
that are not identified and secured will deteriorate quickly; witnesses
who are not identified and interviewed straight away may discuss
events with others and thus contaminate their recollection of the
event or may leave the area and be impossible to trace later; CCTV
images that are not recovered immediately may be recorded over
during the days following the incident and be lost to the
investigation. It is vital that those engaged in the initial investigation
of a crime take positive action to ensure that material is not lost in
this way. They should always investigate the crime as thoroughly as
possible and not merely record the details on the assumption that
the crime cannot be solved or that someone else will carry out an
investigation at a later stage. 
Officers initially deployed to an incident are likely to have a number
of competing demands placed on them as they arrive. Before they
can begin an investigation they may have to: 
• Deal with a violent situation; 
• Provide first aid and call for medical assistance; 
• Reassure victims and witnesses; 
• Prevent public disorder. 
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Once these immediate priorities are dealt with, officers should plan
how best to conduct the investigation. They should use the
investigative strategies which are as applicable to initial investigation
as they are to suspect management and further investigation, see
6 Investigative Strategies. The key factors they should consider are
shown in Figure 4. 
Figure 4 – Initial Investigation
Scene Management 
Key Considerations
Interviews
Identify and 
Who is the investigating
Witness
preserve
officer?
Victim
Offender
Risk management
What is the limit of the initial
attending officer’s role?
Initial Search
Communication
Potential Evidence
Access routes
Recording information
Identify other potential
Exit routes
evidence sources 
Places where offenders
Handover and briefing
are likely to have been
In cases where it appears that a major crime has been committed
such as a homicide or rape, the role of the first officer at the scene is
described in ACPO (2006) Murder Investigation Manual, referred
to hereafter as MIM. In such cases officers should call for assistance
from supervisors. While officers await assistance their priorities
should be: 
• Preserve life; 
• Preserve scenes; 
• Secure evidence; 
• Identify victims; 
• Identify suspects. 
In cases of major crime a supervisor or senior investigating officer
(SIO) will take responsibility for directing activity at the scene. 
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Most crimes reported to the police are not major incidents and
usually the officer who first attends will be the only resource that is
required. This officer may be the investigator throughout the enquiry.
Concluding the Initial Investigation 
In complex investigations it is unlikely that there will be a clear
distinction between the initial investigation and further investigation.
In practice what happens is that once an SIO arrives, the initial
investigation continues to its conclusion. Further investigation
activity is then instigated by the SIO. 
In general, the initial investigation phase will be complete when: 
• The investigator has obtained an account from the victim and
any witnesses who are immediately available (individual force
policy will determine whether these accounts are obtained in the
form of a witness statement (MG11), notebook entry or verbally); 
• The immediate needs of victims and witnesses have been met; 
• The crime scene examination has been instigated; 
• All fast-track actions indicated by the material to hand have
been taken; 
• All records required by the CPIA and individual force policy have
been made; 
• All intelligence gathered during the initial investigation has 
been submitted.
Creating a comprehensive record of all enquiries completed in the
initial investigation will: 
• Assist the investigator to carry out an investigative evaluation; 
• Contribute to the intelligence picture of crime in the area; 
• Enable supervisors to assess the quality of the investigation; 
• Facilitate the handover of the investigation if it is allocated to
another investigator. 
Where the case is allocated to another investigator, a briefing
should be conducted at the conclusion of the initial investigation.
The briefing should include the actions that have been undertaken
and by whom, the decisions that support that action and details of
the material gathered so far. This provides the new investigator with
a clear understanding of events and assists them to prioritise the
investigative actions that will be required to progress the case. 
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Fast-Track Actions 
This term is traditionally associated with major enquiries but should
apply to every investigation whether or not it is using the reactive or
proactive method of investigation. MIM defines fast-track actions as: 
Any investigative actions which, if pursued immediately,
are likely to establish important facts, preserve evidence or
lead to the early resolution of the investigation. 
The time when this type of action can be most decisive is usually during
the initial investigation but the opportunity can occur at any stage.
Fast-track action is particularly appropriate when investigators are
responding to incidents which are still ongoing or have only recently
ended. Material in the form of witnesses, forensic evidence and
articles associated with the crime may be readily available if prompt
action is taken to gather them. 
Whether the crime has been recently committed or not, the first
chance to obtain material may be the last. To delay protecting,
preserving or gathering material may result in it being contaminated
or lost. It is important that every chance to gather material is taken
as soon as possible. 
In larger enquiries SIOs must establish strategies to ensure that new
information is brought to their attention quickly so that fast-track
action can be taken when it is needed. 
4.4.3 Investigative Evaluation 
Progress in a case involves making valid decisions about the value
and meaning of the material gathered and selecting appropriate
lines of enquiry to follow. The investigator has to continually evaluate
material, see 5.5 Investigative and Evidential Evaluation.
In some police forces a crime evaluator conducts a formal
evaluation at the conclusion of the initial investigation process.
A crime evaluator is an experienced investigator who evaluates the
material gathered so far and decides if the crime is to be allocated
for further investigation. 
Most forces have developed policies to guide evaluators on the type
of crimes that will be subject to further investigation and the
resources or units that they will be allocated. 
Even where crimes have been through a formal evaluation process,
investigators should continue to carry out their own evaluations as
new material becomes available. 
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4.4.4 Further Investigation 
Where a crime or intelligence packages are allocated for further
investigation, investigators should develop a clear plan of how they
intend to bring the investigation to a successful conclusion. 
In some cases the initial investigation and the investigative
evaluation will lead to the identification of a suspect and sufficient
material to justify interviewing the suspect under caution, 
eg, where victims or witnesses have made an allegation against 
a named individual. In these circumstances the investigation is 
likely to move straight into the suspect management phase, 
see 6.11 Suspect Strategy. Where this is not the case, further
investigation will focus on gathering material that leads to the
identification of a suspect, see 6 Investigative Strategies.
In either case the investigative plan should be based on a rigorous
evaluation of the material that has been gathered to date and
should include:
• The specific objectives of the investigation, these will depend on
the unique circumstances of the crime and the material that has
already been gathered; 
• The investigative strategies that are to be used to achieve 
those objectives;
• The resource requirement of the investigation. In many cases
this will be limited to the investigator, crime scene examination
and forensic analysis of the material recovered from the scene 
or the suspect. In more complex cases resource allocations will
be greater. It is part of an investigator’s responsibility to
articulate their resource requirement to managers.
Investigators should ensure that all new material is evaluated and
that the investigative plan is revised accordingly. All investigative
plans should be accurately recorded, see 7.7 Record Keeping. 
4.4.5 Suspect Management 
A suspect is defined as: someone who the police would have to
caution under section 10, Code of Practice C PACE 1984 if they
wanted to interview them. 
This definition requires that: 
There must be some reasonable, objective grounds for the
suspicion, based on known facts or information which are
relevant to the likelihood the offence has been committed
and the person to be questioned committed it.
Note 10A of Code of Practice C
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The identification of a suspect provides an opportunity to use a
range of investigative strategies that focus on that individual, 
see 6 Investigative Strategies. 
4.4.6 Evidential Evaluation
This is undertaken when investigators believe there is sufficient
material to justify charging a suspect, see 5.5 Investigative and
Evidential Evaluation. 
It uses the same techniques as the
investigative evaluation but the additional test of admissibility is
applied to the material.
CPS (2011) The Director’s Guidance on Charging provides
information on the referral of cases to the duty prosecutor for a
charging decision. It also includes the action to take in situations
where the duty prosecutor cannot be contacted.
Crown prosecutors work closely with investigators to ensure that
the charges used are the most suitable for the material that
is available.
4.4.7 Case Management 
Once the suspect has been charged, there are a number of matters
which investigators must manage before a case goes to court. The
CPS is responsible for the prosecution of the case after a suspect has
been charged. If further investigative action is required, investigators
will liaise closely with the CPS.
Additional Material 
There is the possibility that new material will become available after
charge. This material may affect the eventual outcome of the case.
If investigators have been thorough during the course of the
investigation, the impact of new material should be minimal. All new
material must be evaluated and any reasonable lines of enquiry that
are identified must be pursued. 
Disclosure 
Part I of the CPIA and CPS (2005) Disclosure Manual contain
specific instructions on disclosure. For further information see
http://www.cps.gov.uk/legal/d_to_g/disclosure_manual/#a002
The investigator has to manage the disclosure process, which includes:
i Retaining all relevant material; 
ii Recording all retained material; 
iii Ensuring that the retained material is revealed to the prosecutor.
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Under the CPIA, it is necessary for the prosecution to disclose
everything that it intends to rely on in court. In addition, anything
which may undermine the prosecution case, assist the defence case
as set out in their defence statement and any unused material must
be disclosed. This duty is a continuing duty and if any further
material comes to the attention of the prosecution, they are obliged
to disclose this to the defence. 
All material is subject to disclosure considerations, whether it has
been used as information, intelligence or evidence. For further
information see
http://www.cps.gov.uk/legal/d_to_g/disclosure_of_third_parties
/index.html 
and
http://www.cps.gov.uk/legal/d_to_g/disclosure_of_previous_con
victions_of_prosecution_witnesses/index.html

File Preparation 
Accurate and full record keeping is essential throughout an
investigation, see 7.7 Record Keeping. Investigators should check
that all records have been fully completed and that there are no
matters to be resolved. There may be reports outstanding from
forensic scientists or other experts and these should be obtained 
and thoroughly checked to ensure that they do not contradict the
prosecution case. 
Exhibit management is an important part of file preparation, see
7.7 Record Keeping. In complex or serious cases investigators
should refer to ACPO (2005) Major Incident Room Standardised
Administrative Procedures (MIRSAP) 
section 12.6 Exhibits. In
volume or series crime it is still a fundamental principle that any
exhibit is properly numbered and labelled, sourced and provenanced
by a witness.
It is the role of prosecutors, defence solicitors and the courts to
thoroughly test the reliability and integrity of the material gathered
during an investigation. A prepared investigator who has used a
methodical and systematic approach to record keeping during the
investigation and file preparation will be able to withstand scrutiny. 
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Defence Liaison 
In most cases, post-charge liaison with the defence will be carried
out by or in association with the CPS. In some circumstances,
however, it may be necessary for the investigator to become involved
in the following: 
• Interviewing witnesses disclosed by the defence; 
• Monitoring the offender while on bail; 
• Responding to defence disclosure. 
Checklists 1 to set out the considerations which an investigator
needs to take into account when preparing for a trial. 
Checklist 1
Suspect Considerations
Bailed 
• Conditions – what are the bail conditions?
• Checks – compliance with bail conditions/frequency 
of checks.
In Custody
• Self harm/suicide;
• Prison notification.
Other Considerations
• Update victim/witnesses whether suspect bailed or in
custody;
• Bail appeals;
• Prepare schedule of offences to be taken into
consideration (TIC);
• Defence statements and alibi notices;
• Disclosure – sensitive material (PII);
• Obtain outstanding material – Custody Time Limits –
Prosecution of Offences (Custody Time Limits)
Regulations 1987;
• Liaison – CPS, case conferences, briefing counsel.
Risk Assessment of Suspect Safety.
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Checklist 2
Victim and Witness Considerations 
Continual Liaison
• Suspect bail conditions/amendments;
• Risk assessment – safety plans/protection/intimidation;
• Court familiarisation visit;
• Liaison with victim and witness support;
• Special measures.
Antecedents – consent for medical history. 
Availability 
• Witnesses – experts;
• Interpreters;
• Floating cases;
• Convey to court and conduct money.
Victim Personal Statement Scheme 
• Compensation/Criminal Injuries Compensation Authority
(CICA).
Additional Statements. 
Notification of other Agencies Involved, eg, Social Services.
Witness Protection.
Discontinuance. 
Checklist 3
Investigator’s Considerations 
Pre-trial Reviews – attendance. 
Forensic Results – secondary submissions. 
Defence Disclosure – review of material. 
Court Security – liaison with court staff and provision of resources 
• Jury interference;
• Trial relocation.
Exhibit Location/Storage and Handling. 
Review Statements and File. 
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Investigative 
Decision Making
This section details the decision-making process
employed by investigators, and the factors which may
affect decision making. It also proposes a number of
measures, including the investigative mindset and
investigative and evidential evaluation, to assist
investigators in making accountable decisions and to
minimise the chance of errors.

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5: Investigative Decision Making
Contents
5.1
Investigative Decision Making
81
5.2
How Investigators Make Decisions
81
5.2.1 Limited Personal Experience
81
5.2.2 The Unconscious Nature of Working Rules
82
5.2.3 Personal Bias
82
5.2.4 Verification Bias
82
5.2.5 Availability Error
83
5.2.6 Other Factors Which Can Affect
Decision Making
83
5.3
The Investigative Mindset
84
5.3.1 Understanding the Source of Material
85
5.3.2 Planning and Preparation
85
5.3.3 Examination
86
5.3.4 Recording and Collation
88
5.3.5 Evaluation
89
5.4
Applying the Mindset
89
5.5
Investigative and Evidential Evaluation
90
5.6
The Evaluation Process
91
5.6.1 Objectives
92
5.6.2 Material Filters
93
5.6.3 Organising Knowledge
95
5.6.4 Testing Interpretation
98
5.7
Hypotheses
99
5.7.1 Developing Hypotheses
100
5.7.2 Testing Hypotheses
101
5.8
Decision Support
103
Checklists
Checklist 4 Examination of Material
86
Checklist 5 Building Hypotheses
102
Figures
Figure 5 Investigation and Evidential Evaluation
92
Figure 6 Gap Analysis Matrix
97
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5: Investigative Decision Making
During an investigation, decisions must be made on a number of
5.1 Investigative
issues. Decision making is, therefore, central to any criminal
Decision Making
investigation. A core skill for any investigator is the ability to make
decisions which can be justified to others. Despite this, decision-making
skills are not generally part of investigator training.
A decision is a choice between a variety of alternatives
and a decision maker is whoever makes such a choice.
A decision can be made instantly but more often involves
the decision maker in a process of identification, analysis,
assessment, choice and planning.
Heller (1998) 
Flawed decision making has been responsible for failed investigations
and miscarriages of justice see, for example, the Shipman Inquiry
Report, 
the Byford Report, the Stephen Lawrence Inquiry Report.
Failures in decision making are not only confined to major
investigations or difficult cases. For further supporting information
see Home Office (2004) Reviewing murder investigations: an
analysis of progress reviews from six police forces.

Relatively little research has been conducted into the ways in
5.2 How
which investigators make decisions. They usually rely on a set of
Investigators
working rules (or heuristics) that they develop from their
Make Decisions
experience of conducting investigations. They also learn working
rules from colleagues.
These working rules enable investigators to understand the
situations they are faced with and provide a framework which helps
them to understand the material they gather. Working rules are an
efficient means of making decisions and generally present few
problems. However, they do have a number of limitations which
investigators should be aware of if they are to avoid making
inappropriate decisions.
5.2.1 Limited Personal Experience
There has been a tradition in the Police Service of learning on the
job. The resulting range of working rules that investigators have
depends on their personal experience. As a consequence an
investigator’s ability to make decisions may be limited by the extent
of their experience and the degree to which they are able to adapt 
it to any given situation.
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5: Investigative Decision Making
As the unique experience of each investigator contributes to the
working rules they acquire, there will be considerable variation in the
way that different individuals make decisions during investigations.
Some variation is inevitable, and even desirable, but this can cause
difficulties in designing and implementing audit regimes and judging
individual performance.
5.2.2 The Unconscious Nature of Working Rules 
Working rules can become so familiar to investigators that they 
are not always aware that they are using them. This may lead to
difficulties in describing how a particular decision was reached.
Investigators may refer to these decisions as being based on
hunches, gut reaction or intuition, and are unable to explain the
rationale behind them, making it difficult for others to understand
the decision-making process. In principle there may be nothing
wrong in following hunches or gut reactions, but the investigator
must expect to account for their decisions to others including victims,
witnesses, supervisors, managers, and/or to partners in the criminal
justice system. 
5.2.3 Personal Bias 
There are occasions when decisions are unconsciously affected by
personal perceptions of people, places and situations. Racism, sexism
or homophobia can influence the thought process without the
individual realising the effect that they are having. 
Individual biases can affect decision making. For example, an
investigator attends the scene of a domestic burglary and decides
not to conduct house-to-house enquiries in the vicinity because of 
an assumption that no one will tell them anything worthwhile. In this
situation, the opportunity to gather information from the immediate
neighbours is missed and this may have a detrimental effect on
the investigation.
5.2.4 Verification Bias 
If investigators develop an early view as to what has occurred or who
is responsible for a crime, there is a danger that they focus on the
material that supports that view. This can result in a situation where
they only gather material that supports their view, thus reinforcing
their opinion that their view is correct. This will lead investigators to
ignore alternative lines of enquiry or sources of material.
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5: Investigative Decision Making
Investigators should avoid taking too firm a view on any point until
they have gathered the maximum amount of material. Where
information levels are low, well-developed hypotheses can be
powerful tools and their use is discussed in 5.7 Hypotheses. 
5.2.5 Availability Error 
There is a danger that an investigator will base their decisions about
the investigation on material that is vivid and memorable, dramatic,
emotionally charged or easy to visualise. Such material might be
psychologically compelling because it appears to be familiar or is
linked to a memory, but it may not necessarily reflect the material 
at the investigator’s disposal. 
Investigators should maintain an open and objective approach to
gathering material and be prepared to challenge their own
reasoning behind a decision. Using the investigative mindset and
challenging personal perceptions will assist the investigator in
avoiding availability error. 
5.2.6 Other Factors Which Can Affect Decision Making 
There are a number of other factors which may also adversely affect
the quality of decision making. While no one can rid their mind of
these ingrained flaws, anyone can learn to understand the traps and
compensate for them (Hammond et al, 1998). Factors which may
affect decision making include: 
• Sweeping statements which over generalise and ignore
contradictory evidence; 
• Oversimplifying the facts by assuming clearly defined boundaries
when it is not possible to do so; 
• Making inferences from the particular to the general, eg,
assuming that because some are, all are; 
• Begging the question, eg, taking things for granted which have
not yet been proved;
• Special pleading, eg, stressing only one view point and ignoring
other more relevant or plausible opinions because they conflict
(the arrogance of experience); 
• Potted thinking, ie, using simplistic assertions in an
unwarrantable fashion, eg, slogans or catchphrases in arguments;
• Early assumptions about material or a source of material which
can potentially misdirect the focus of an investigation and cause
relevant material to be overlooked; 
• Investigators can become overwhelmed by information, which
may result in the investigation losing direction or focus; 
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• Building unlikely hypotheses that do not reflect the known facts,
ultimately causing the investigation to become misdirected, or
an opportunity to be overlooked; 
• Wasted effort caused by investigative actions which, although
satisfactory, may be time-consuming but not optimal to 
the investigation;
• Poor examination or evaluation of material (including
investigative interviewing), which may cause relevant lines of
enquiry to be overlooked; 
• Underestimating the importance of victims or witnesses. A polite
but disregarding approach by investigators may potentially
cause victims and witnesses to become unhelpful or apathetic 
to the investigation or subsequent criminal proceedings. 
All of the above limitations can have a detrimental effect on the
quality of the decisions made by investigators but by being
conscious of them, investigators can adopt a disciplined approach 
to decision making. 
There are dangers in overstating the extent to which the use of
investigators’ working rules for decision making are problematic.
All occupational groups develop and use such rules and in reality
there is no effective alternative. Investigators must, however, be
aware of the potential pitfalls, and actively challenge their personal
perceptions and understanding. 
The application of an investigative mindset will bring some order to
5.3 The
the way in which investigators examine material and make decisions.
Investigative
There is no process map that will assist the investigator to develop
Mindset
the mindset: it is a state of mind or attitude which investigators
adopt and which can be developed over time through continued use.
It involves applying a set of principles to the investigation process.
This will enable investigators to develop a disciplined approach which
ensures that the decisions they make are appropriate to the case, 
are reasonable and can be explained to others. 
The investigative mindset can be broken down into five principles:
• Understanding the source of the material; 
• Planning and preparation; 
• Examination; 
• Recording and collation; 
• Evaluation. 
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5.3.1 Understanding the Source of Material 
An understanding of the provenance and characteristics of the
source of material is essential in order to conduct an effective
examination of it. This will enable investigators to identify any
characteristics particular to the source which may determine the way
it is examined, eg, whether special measures are available to assist
victims and witnesses. For further information on special measures,
see 3.9 Youth Justice and Criminal Evidence Act 1999. 
Understanding the nature of the source will assist investigators to
determine what the source can contribute to the investigation, 
and to explain its characteristics and relevance to others.
Understanding the Source of Material 
Example: When examining CCTV images, investigators should
know the camera from which the image was taken, the type of
equipment that was used and the timescale of the images (such
as time lapse or continuous loop). They should know the location
shown in the image and the area immediately around it so that
they can determine where people in the image are coming from
and going to. They should identify any blind spots in the area
covered by the camera (eg, behind vehicles, in doorways), know
the time the image was taken and how these factors relate to
the offence being investigated. This information will enable
investigators to interpret the material shown in the image
accurately, explain the image to others and justify their
interpretation of it. 
5.3.2 Planning and Preparation 
Usually, the first opportunity to examine a source of material is the
only opportunity. The process of scene examination will invariably
alter a scene and it is, therefore, important to get it right first time.
The recollection that victims and witnesses have of events will fade 
or become contaminated by versions of events they later hear from
others and so it is essential that all of the material they can provide 
s obtained as early as possible. The same principle applies for many
other sources of material. 
Careful planning is required to ensure that the examination reveals
all the available material that the source can provide. Investigators
should work through Checklist 4. In complex or difficult cases, they
should also consider producing a written plan before commencing
the examination to ensure that important points are not overlooked. 
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Checklist 4
Examination of Material
• Set clear objectives for retrieving the material from the source.
• Identify the most appropriate method of carrying out the
examination. In some cases there will be legal or policy
requirements that govern the method of examination.
In other cases there will be technical requirements that must
be met. 
• Identify the need for specialist equipment or expertise.
Some examinations, such as video interviews and viewing
CCTV tapes, require specialist equipment which may have to
be booked in advance. In other cases experts such as
forensic scientists or pathologists may be required. Access to
specialist equipment and expert support is usually governed
by force policy and investigators should familiarise
themselves with this when planning the examination. 
• Identify the most appropriate location for the examination.
In the case of a victim or witness interview, this will include
consideration of whether the location is suitable and meets
the requirements of relevant legislation. The examination
of other sources may only require that the location is
adequate in terms of the volume of material to be
examined, the level of security required and the need to
house any specialist equipment.
If investigators do not have the necessary knowledge to
enable them to draw inferences from the material, they should
seek further help and information.
5.3.3 Examination 
The process of examination can be divided into three separate areas.
The extent to which any area is relevant to a particular examination
is determined by the source and its characteristics. Examination will
usually include: 
• Account; 
• Clarification; 
• Challenge. 
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Account 
In interview situations, victims, witnesses and suspects are
encouraged to provide an account of their knowledge of, or
involvement in, the incident. When examining other sources of
material, the account will be interpreted by the person carrying 
out the examination. For example, an investigator may infer that 
the offender entered the scene of a burglary through the window
because it has been forced open from the outside, or that a person
seen in a CCTV image may be the offender because they are
wearing a distinctive item of clothing as described by a witness. 
Those carrying out such examinations should be in a position to
explain their findings or interpretations to others. They should also
consider alternative explanations, see 5.7 Hypotheses. 
The degree of difficulty involved in inferring an account from a
source largely depends on the nature of the source, any legal or
procedural considerations relating to how the material must be
treated, and the level of material that investigators already have.
The more material investigators have about a crime, the easier it 
will be to draw inferences about the contribution a source can make
to the investigation. 
Where the source of material is a victim, vulnerable, intimidated or
significant witness or offender, an account should be obtained using
the Ministry of Justice (2011) Achieving Best Evidence in Criminal
Proceedings: Guidance on interviewing victims and witnesses,
and guidance on issuing special measures, 
Third Edition.
Clarification 
Having obtained an account from the source, investigators should
clarify any inconsistencies or ambiguities that it contains. This may
involve testing it against other material already gathered or
identifying actions to acquire further material to clarify it. For
example, when viewing a CCTV image, the events shown may, on
first consideration, appear to verify a witness account of an incident.
However, the time shown on the image may be inconsistent with
the time of the incident given by witnesses. Testing the accuracy of
the clock on the CCTV system that generated the image would
lead to material which either confirms or casts doubt on the
witnesses’ reliability. 
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Challenge 
Experience shows that even those sources of material which at first
appear to be of unquestionable reliability can be wrong, and that
material that appears to indicate one thing can later be found to
support a totally different interpretation. Investigators should,
therefore, continually challenge both the meaning and the reliability
of any material they gather. Investigators should treat all material as
possibly being wrong and regard all sources of material as potentially
misleading. This is summed up by the ABC approach: 
Assume nothing; 
Believe nothing; 
Challenge everything. 
Every account should be checked for inconsistency or conflict with
other material. Investigators are most likely to be misled because 
hey have not paid attention to detail. Prima facie assumptions should
never be made and material should never be accepted without
question. Investigators should constantly search for corroboration.
5.3.4 Recording and Collation 
Before closing the examination of a source of material, investigators
should consider the following: 
• The records that need to be made of the examination; 
• If required, how the source is to be stored; 
• The security of the source; 
• Access arrangements to the source if it is under third-party control.
Where the source is to remain in the control of a third party, they are
not obliged to do anything in relation to this material. This is why the
code suggests to invite them to retain the material.
Section 3.6 of the CPIA Code of Practice, under Part II of the Act,
states that any third party in possession of material which may
be relevant to an investigation should be informed of the
existence of the investigation and invited to retain the material
in case they receive a request for its disclosure. 
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5: Investigative Decision Making
5.3.5 Evaluation 
Evaluation should identify any immediate actions that need to be
taken in relation to the source or the material that was gathered
from it. These include actions to test the reliability of the source or
the material gathered from it, or any fast-track actions that may be
needed to secure other material. 
Applying the investigative mindset to the examination of all sources
5.4 Applying
of material will ensure that: 
the Mindset
• The maximum amount of material is gathered; 
• Its reliability is tested at the earliest opportunity; 
• Immediate action is taken in relation to it; 
• Relevant records are made; 
• The material is appropriately stored. 
The first opportunity to examine a source of material and test its
reliability may be the last. In addition, where there is an opportunity
to gather material early in an investigation it must be taken. To pass
up such opportunities may mean that they are lost forever, see
4.2.3 The Material that Is Admissible as Evidence.
In applying the investigative mindset investigators should be mindful
of the limitations in decision making, see 5.2 How Investigators
Make Decisions. 
In particular, they should guard against being
influenced by their first impression of the material. This is particularly
true of material gathered from victims, witnesses and suspects in the
early stages of an investigation when they may still be traumatised
or under stress caused by the commission of the offence. Those who
appear to be reluctant to assist, or even hostile, may have useful
material which, if dealt with correctly they will share with
investigators. Conversely, those who appear compliant or willing 
may be presenting self-serving versions of events.
Investigators must keep an open mind and be receptive to
alternative views or explanations, see 6.5 Victim and Witness
Strategy. 
Inv
estigators should never rush to premature judgements
about the meaning of any material or the reliability of its source.
Accepting the material at face value risks overlooking alternative
sources of material or alternative interpretations, thereby losing the
opportunity to examine them.
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The application of the investigative mindset from the outset assists
investigators in identifying areas which require development or
challenge through further investigative action. It also helps them to
make structured and auditable decisions. 
Material which has been gathered during an investigation should be
5.5 Investigative
subjected to a periodical formal evaluation. This will allow the
and Evidential
investigator to review the progress of the investigation. Evaluation
Evaluation
enables investigators to ‘step back’ from the rush of investigative
action and to consider the investigation in ‘slow time’. Even though
an investigation may appear to be straight forward, investigators
should always be encouraged to take this step back and formally
evaluate the material, exploring whether any additional lines of
enquiry can be identified and ensuring that all existing lines of
enquiry and investigative actions have been pursued and completed.
It also allows investigators to review the actions and decisions
already taken. This process of evaluation is as relevant to volume
crime investigations as it is to more serious or complex investigations. 
Investigators must follow a standard model of evaluation as this will
enable them to become competent in its use, and allow them to
evaluate material in a consistent, structured and auditable format.
There are two types of formal evaluation which should be carried out
during an investigation. Investigative evaluation should identify: 
• What is known; 
• What is not known; 
• Consistencies; 
• Conflicts. 
Evidential evaluation should consider: 
• The overall strength of the case; 
• Whether sufficient evidence exists against the offender to
proceed to charge. 
In practice, both evaluations may be carried out more than once
during an investigation using the same method (for ease of reference
these are explained together). During the early stages of an
investigation, a greater emphasis should be placed on investigative
evaluation in order to identify a suspect. Later, and particularly during
the suspect management phase of the investigation, the emphasis
will change to ensuring that an evidentially robust case can be passed
to the CPS for prosecution purposes.
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In some forces an initial investigative evaluation may be carried out
by a crime evaluator after the initial investigative stage. The crime
evaluator will determine whether further investigation is required. 
Where a large amount of material has been gathered during the
investigation, an assessment should be made in a calm and
structured environment. Investigators should also consider the use 
of analysts, see 6.6 Intelligence Strategy. 
In all cases investigators must record the outcome of an evaluation.
If it is not possible to identify further investigative action and all
existing lines of enquiry have been pursued, this should be clearly
recorded, see 7.7 Record Keeping. 
The key differences between investigative and evidential evaluation
are that during an investigative evaluation, investigators are free to
use all available material even though it may not be evidentially
admissible. When carrying out an evidential evaluation, investigators
need to assess the strength of the case taking into account only the
evidentially admissible material, see 5.6 The Evaluation Process.
The process of evaluation advocated in this practice advice is shown
5.6 The Evaluation
in Figure 5. It identifies the current objective(s) of the investigation
Process
and considers the material when tested against the filters of
relevance, reliability and admissibility. The material is then scrutinised
in line with the objective(s), to determine what it can tell the
investigator. By recording the outcome in a grid matrix, see Figure 6
and 5.6.3 Organising Knowledge, the investigator will gain an
overview of the case showing the areas that require action. 
The process of evaluation is explained in more detail under 
the headings:
• Objectives; 
• Material Filters
– relevance
– reliability
– admissibility;
• Organising Knowledge; 
• Testing Interpretations.
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Figure 5 – Investigative and Evidential Evaluation
Objectives
Material
• Relevance
• Reliability
• Admissibility
WHO
WHAT
WHEN
WHERE
WHY
HOW
KNOWLEDGE
Outcome
Lines of Enquiry
5.6.1 Objectives 
An investigator must be clear about the objective that is to be
achieved when carrying out an evaluation. In the early stages of an
investigation, the objectives are likely to be broad and concerned
with establishing issues such as: 
• Has a crime has been committed? 
• Who is the victim? 
• Are there any witnesses? 
• Where or what is the scene? 
• Can a suspect be identified? 
• What material can be gathered? 
As the investigation progresses, these objectives will narrow. During
the course of the investigation, various objectives will be achieved
and not reviewed every time an investigative or evidential evaluation
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is carried out. For example, whether a crime has been committed 
and the type of crime are likely to be established early in the
investigation, and the objective may narrow to questions such as: 
• Can a suspect be placed at the scene at the time the crime 
was committed? 
• Can a suspect’s alibi be corroborated? 
The objective will vary depending on the crime, the available material
and the stage of the investigation. The evaluation process is
sufficiently flexible to accommodate such changes in the objectives. 
5.6.2 Material Filters 
The term material has been defined in 4.1 Material. When carrying
out an investigative or evidential evaluation, the relevance, reliability
and admissibility of the material gathered should be established first. 
Relevance 
The CPIA Code of Practice states that: 
Material may be relevant to an investigation if it appears to an
investigator, the officer in charge of an investigation, or to the
disclosure officer, that it has some bearing on any offence under
investigation or any person being investigated, or on the surrounding
circumstances of the case, unless it is incapable of having an impact
on the case.
In light of this a wide view should be taken of the term relevance
and as much material as possible should be used in the evaluation
process. Investigators should only exclude material as irrelevant
after careful consideration or consultation with the disclosure officer
(where this role is being carried out by a separate investigator) or a
crown prosecutor (who has ultimate responsibility to decide which
material will be used in the case). If in doubt, investigators should
always err on the side of caution as a decision to exclude material
as irrelevant may later be called into question in any subsequent
proceedings. For further information see Part I of the CPIA and
CPS (2005) Disclosure Manual, Chapter 5.
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Reliability 
Through the use of the investigative mindset, the reliability of
material should already have been established. It is, however, prudent
to review the reliability of material during the evaluation process to
ensure that any potential problems have not been overlooked. 
Where sources of material are victims, witnesses or suspects,
investigators must avoid making judgements about the reliability 
of the material they produce based on factors such as lifestyle,
previous offending history or associates, as these may not be
relevant to the investigation in hand. Such factors clearly have the
potential to adversely affect the quality of the evaluation.
Investigators should always look for independent corroboration of
the account provided by the source, which will increase the weight
that can be given to it. Where the source of material is a suspect,
investigators should keep in mind the revised rules on bad character
introduced by the CJA, whereby in certain circumstances previous
offending behaviour may be relevant to the current investigation.
See 6.11.10 Suspect Interviews. 
If a victim or witness account cannot be independently corroborated,
the prosecution or the defence may challenge the reliability of their
evidence when it is presented in court. Investigators should
anticipate such challenges and consider providing alternative
material which may help the court to assess the reliability of the
source. This may include evidence of character, or evidence that the
source has been consistent in their account over a period of time. 
Investigators should have a clear understanding of the impact the
reliability of material may have on the investigation and the strength
of the prosecution case. If they are in any doubt, they should consult
a crown prosecutor for advice. 
A clear understanding of the reliability of the material will enable
investigators to determine the weight they should give to it in the
evaluation. The following may assist investigators to determine the
appropriate weight a piece of material should be given: 
• Material that can be corroborated by an independent source 
will have high reliability;
• Material that can only be corroborated by a person such as a
spouse or other relative will have less reliability; 
• Material that cannot be corroborated and conflicts with other
material gathered in the investigation will have less reliability; 
• Material indicating other factors which may cast doubt on the
reliability of the material, see 3.2 Best Evidence. 
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Admissibility 
When investigators carry out an evidential evaluation, they should
apply the additional test of admissibility. This will help to ensure that
the maximum amount of material will be available to the courts in
an evidentially acceptable format. 
Following the introduction of statutory charging, the decision
whether or not to charge a suspect now largely falls on the CPS, 
see 3.6.3 Charging Standards. Investigators should, therefore, 
work closely with the crown prosecutor to determine what constitutes
an acceptable evidential format in relation to any material.
Forethought and planning will maximise the amount of material 
that will be accepted as evidence. 
5.6.3 Organising Knowledge
Material gathered by investigators provides them with knowledge 
of the incident they are investigating. This material usually consists
of many types, and may include victim and witness statements,
exhibits and images, intelligence reports, lists of active offenders in
the area and forensic science reports. The evaluation process will
help them to organise their knowledge so that they can identify
what action is needed next. How they organise this knowledge of
the offence will, to a large extent, depend on the objective they are
seeking to achieve.
In the first instance the objective is likely to be broad and concerned
with establishing what information there is, what type of incident is
being investigated, whether or not a crime has been committed and
if there is a suspect. The 5WH formula (Who – What – When –
Where – Why – How) has been found to be a highly effective way in
which investigators can organise their knowledge in the early stages
of an investigation. 
Identifying gaps in their knowledge of an offence and potential lines
of enquiry may be a reasonably straight forward matter for the
experienced investigator. Gaps may also flow naturally from the
initial investigation by applying the investigative mindset. 
It may not always be clear, however, exactly what the investigator is
missing. By applying the 5WH formula to the material, investigators
can pinpoint specific gaps in the case which may suggest potential
lines of enquiry. 
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• Who are the victim(s), witnesses and suspect(s)? Is there a
physical description or other evidence which may assist in
identifying the suspect? Are there any characteristics of 
the victim which suggest a possible offender, race, age,
particular vulnerabilities?
• Where did the offence take place? Is there any evidence of
selectivity? Does there appear to be an element of planning or
does either the location and/or the victim appear to be random?
Are there characteristics of the location that may be significant,
eg, sheltered housing or vulnerable commercial premises? 
• What has occurred? It is important to establish what has
happened. This may be immediately obvious, but in some cases
the investigator will have to piece together the available material
by locating witnesses, interviewing victims and suspects,
developing intelligence or building reasonable hypotheses.
What was stolen? Were any tools or special techniques used? 
• When did the offence and other significant events take place? 
• Why was this offence committed in this location against this
victim at this time?
• How was the offence committed? Assess the offender’s use of
skills and/or knowledge.
This list is not exhaustive but illustrates the way in which the material
can be ordered. 
Figure 6 may assist investigators to organise the material available
to them and identify areas which require further investigation. It will
also highlight conflicts and inconsistencies in the material, thereby
allowing the investigator to pre-empt any evidential problems which
may arise later.
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Figure 6 – Gap Analysis Matrix
What Is Known
What Is not Known 
Conflicts
Consistencies
WHO
WHAT
WHEN
WHERE
WHY
HOW
Subsequent evaluations will replace the broad objectives (eg, who,
where, what) with more specific objectives, such as identifying the
suspect. The way in which investigators then choose to organise their
knowledge will change to match this more specific objective, eg: 
• Description – does the individual fall within the suspect
parameters?
• Availability – was the individual available to commit the
offence within the time parameters? 
• Physical links – can the individual be linked to the crime through
articles removed from or left at the scene? 
• Forensic links – can the individual be linked to the crime through
forensic science techniques? 
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• Identification links – can the individual be linked to the crime
through victim or witness identification? 
• Intelligence links – is there intelligence linking the individual to
the crime?
• Behavioural links – is there anything about the individual’s
previous behaviour that may link them to the crime? 
The factors used to organise knowledge will change depending 
on the objective and the unique circumstances of the crime. By
organising knowledge in a rigorous and systematic fashion,
investigators will ensure that they extract the optimum information
from it.
5.6.4 Testing Interpretation 
Subjecting the material to an evaluation will identify what is known
and what is not known and what is consistent in the investigation
and what is inconsistent. Investigators can use this information to
progress the investigation or to improve the amount of evidence
available to support a charge. 
The material gathered during an investigation may be interpreted 
in a number of ways. If the investigative mindset has been applied
rigorously throughout the investigation, the reliability of the material
will already have been checked and its meaning will be as clear as it
is possible to be at this stage. Despite these checks, it is likely that the
interpretation of some material will be difficult and that the meaning
placed on it by investigators may be open to challenge. 
There are a number of ways in which investigators can test the
validity of the interpretations they put on material. 
• Self-assessment: Investigators should thoroughly check their
work and review any assumptions they have made during the
evaluation process; 
• Peer assessment: Checks by supervisors or colleagues provide 
a second opinion on the interpretation of material; 
• Expert assessment: Where investigators use material produced
by experts such as forensic scientists, they should consult the
expert to ensure that the outcome of the evaluation is consistent;
• Formal review: In complex cases a formal review of the
investigation can be carried out by a suitably qualified officer. 
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If a case is to go to charge, further checks will arise out of the crown
prosecutor’s review of the Report to Crown Prosecutor for a Charging
Decision (MG3). Early consultation with the crown prosecutor may
identify and develop additional lines of enquiry and/or evidential
requirements, or any pre-charge procedures. It may also assist in
identifying evidentially weak cases that will not be rectified by further
investigation, thereby avoiding wasting time and resources. 
Hypothesis is defined as:
5.7 Hypotheses
…a suggested explanation for a group of facts either
accepted as a basis for further verification or accepted as
likely to be true.
Collins English Dictionary (2004) 
Another way of describing a hypothesis is building a scenario that
best explains the available material. 
Hypotheses can assist investigators to progress investigations.
Before deciding to use hypotheses, the investigator must consider
the following: 
• Has all the available material been gathered? 
• Does the investigator understand all the material? 
• Are there lines of enquiry which have not yet been pursued and
which could generate more material? 
• What benefit will the use of a hypothesis bring to the investigation?
The decision to use hypotheses will depend on the amount of
material available to the investigator. In general, investigations make
progress because the material gathered generates actions, which in
turn generate more material. This process continues until sufficient
material has been obtained to identify a suspect and support a
prosecution. Frequently, the link between material and the action
that follows is straightforward and does not require an investigator
to form hypotheses. 
There will be occasions, however, when the amount of material
available does not readily identify the action that can be taken to
further the investigation. In such cases hypotheses may enable the
investigator to regain the momentum of the investigation. 
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The investigator should apply the investigative mindset to locate,
gather and use material. Once this has been done, the material
should be evaluated using the investigative and evidential evaluation
process, see 5.5 Investigative and Evidential Evaluation. This will
ensure that investigators fully explore the potential of all the material.
It will also indicate if further action is necessary to progress the case.
Hypotheses can also be used to test if the interpretation that has
been put on the material gathered is the most reasonable one.
Developing alternative hypotheses from the same material may
direct further enquiries that help to confirm which interpretation 
is likely to be true. This is not only useful during the investigation,
when it will help guide the investigator’s decision making, but it is
also a useful way of anticipating the type of interpretations that 
will be put on material in court.
During the early stages of a case, investigators often have little
information they can be certain of. In these circumstances
investigators should avoid trying to fill any gaps in the material with
hypotheses about what may have happened. Hypotheses that are
formed from limited or uncertain information can, at best, only
amount to an assumption of what may have occurred and this 
could be influenced by personal bias or stereotyping.
5.7.1 Developing Hypotheses
Before developing hypotheses, investigators must have sufficient
knowledge to make valid judgements. If not, they should seek
assistance from colleagues or a supervisor. In serious or complex
investigations they may need to request assistance from a
Behavioural Investigative Adviser (BIA) from the NPIA Specialist
Operations Centre.
Hypotheses should have a specific objective based on the gap or the
conflict in evidence, eg, how did the victim get from home to the
scene? All material relevant to an investigation should be
considered and any assumptions or inferences that are made during
this process should be explicitly recorded. A hypothesis should be a
reasonable interpretation of the material available and should
offer the most logical explanation of the facts as they are known.
It is likely, however, that there will be no single most logical
explanation, but rather a series of hypotheses, each of which offers
an alternative explanation.
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Hypotheses are generally improved if they draw on the knowledge of
those who have experience in the relevant area.
During the investigation of a burglary, a suspect is arrested 
as a result of fingerprint identification. The suspect answers 
no questions during interview and is charged with the offence.
A search of his home at the time of arrest fails to locate the
jewellery stolen during the burglary. There is a good description
of the jewellery and it should be relatively easy to identify. There
is no specific information on where the jewellery might be and
the investigator decides to develop a number of hypotheses as
to where material relating to the disposal of the jewellery may
be found. These hypotheses may indicate that the suspect:
• Sold the jewellery to a third party; 
• Hid it in an as yet undiscovered place; 
• Disposed of it by other means (eg, has thrown it away,
traded it or broken it down to make different items); 
• Did not commit the burglary alone; or
• That the victim is exaggerating their loss. 
The investigator is seeking to identify additional material or
intelligence which would locate the missing jewellery and/or link
the suspect or a third party to its disposal. 
The above scenarios will generate several potential lines of
enquiry which will require further investigation (eg, enquiries
with relatives or associates, visits to second-hand dealers or
jewellers, tasking CHIS and/or accessing intelligence systems)
and which may or may not identify additional material to assist
the investigation.
5.7.2 Testing Hypotheses
The purpose of developing and testing hypotheses is to enable
investigators to seek further material or to test an interpretation put on
material. By acquiring further material, one particular hypothesis may
be shown to be correct.
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The material gathered as a consequence of a single hypothesis 
can provide positive reasons to discount all others. In the previous
example, in 5.7.1 Developing Hypotheses, confirmation that the
jewellery was sold in a car boot sale will discount all of the other
hypotheses. In other cases it may be possible to discount a single
hypothesis without establishing how the jewellery was disposed of.
For example, if all of the local second-hand dealers have credible
records and CCTV which does not show the offender selling the
jewellery, this method of disposal can be discounted. This does 
not, however, explain how the jewellery was disposed of, but 
may at least discount one explanation and allow effort to be
focused elsewhere. 
Making judgements about hypotheses can be difficult. The decision
that the local second-hand dealers were not used to dispose of the
jewellery relies on the records they keep. There could be another
method of disposal that the investigator did not think of. For this
reason, hypotheses should only be used when absolutely necessary.
They should be based on known facts and stated assumptions, and
should only be made by those with knowledge of the relevant risks.
They should be constantly reviewed and where they concern a vital
element of the investigation must be thoroughly and regularly
reviewed by an independent investigator or a supervisor.
Checklist 5
Building Hypotheses
Considerations that have to be met when building hypotheses: 
• Ensuring a thorough understanding of the relevance and
reliability of all material gathered; 
• Ensuring that the investigative and evidential test has been
applied to all the material gathered in the investigation; 
• Ensuring there is sufficient knowledge of the subject matter
to interpret the material correctly; 
• Defining a clear objective for the hypothesis; 
• Developing hypotheses that ‘best fit’ with the known material; 
• Consulting colleagues and experts to formulate hypotheses; 
• Ensuring sufficient resources are available to develop or test
the hypotheses; 
• Ensuring that hypotheses building is proportionate to the
seriousness of the offence. 
For more information on the use of hypotheses, see ACPO (2008) 
Practice Advice on Analysis.

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Support for investigators is available both internally and externally 
5.8 Decision
to the Police Service. Supervisors and mentors, colleagues, accident
Support
investigators, crime scene examiners, managers, interviewers and
interview advisers are all internal sources. Forensic science staff and
scientists are examples of external sources. 
Force crime review teams can provide information and circulate good
practice, in person, to individuals and throughout the organisation to
assist with informed decision making. 
Support for investigation decision making is also available from 
the NPIA Specialist Operational Support (SOS). It comprises four
sections: Specialist Operations Centre (SOC); Crime Operational
Support (COS); Serious Crime Analysis Section (SCAS); Uniform
Operational Support (UOS). 
Available Support
Specialist Operations Centre (SOC) provides a single point 
of contact for police forces and key partners requesting
information, advice or support in relation to covert techniques,
major crime, critical incidents and uniform operations. SOC
provides the following:
• Advice on the lawful and effective use of covert
techniques. This team provides, on behalf of ACPO, a
single source of advice on the lawful and effective use 
of covert techniques and strategies. This advice has a
particular focus on legislation, case law, national policy
and good practice.
• Advice from, and if required access to, the deployable
resources of the Crime and Uniform Operational Support
teams regarding: 
– the investigation of murder, no body murder, rape,
abduction, suspicious missing persons, and series 
sexual offences;
– advising on and sourcing external expertise to an
investigation via the NPIA Expert Advisers Database;
– public order, operational planning and the policing of
major incidents;
– disaster management debriefing and the police use 
of firearms.
• Information on the NPIA Practice Improvement Unit
(Publications and Assisted Implementation).
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Crime Operational Support (COS) – teams of experts can
deliver tailored advice to senior investigating officers dealing 
with serious crime investigations including murder, rape, series
and serious sexual offences, abduction, suspicious missing
persons and no body murder investigations (though other 
cases may be considered). The support may include some of 
the following:
• Regional Advisers (RAs) can, at the SIO’s request, offer
strategic and tactical advice, and practical support to
investigators of serious and series crimes, and other complex
enquiries including cross-border and high-profile cases.
They identify good practice through review teams and
investigation debriefs. 
• Crime Investigation Support Officers (CISOs) provide
tactical advice and guidance with knowledge of, and access
to, the whole range of NPIA support services and products.
They also provide out-of-hours access to the Specialist
Operations Centre’s Expert Advisers Database.
• The National Search Adviser has a national remit to
provide operational support to forces and relevant agencies
in relation to search matters which are crime linked. 
• The National Interview Adviser is available in cases which
are complex due to multiple suspects or where witness
testimony is likely to be the key. The adviser can provide
advice and guidance on all aspects of interviewing suspects,
victims and witnesses. The adviser works closely with SIOs,
investigating officers and interviewing officers to develop
bespoke interview strategies.
• The National Family Liaison Adviser may be beneficial in
complex investigations where there are suspects within the
family or other sensitivities exist.
• Behavioural Investigative Advisers (BIAs) provide a
range of investigative support and advice that draws on
behavioural science principles, theories and research. BIAs
can help with examining and developing hypotheses,
informing decision making and providing theoretical and
empirical considerations at each stage of the enquiry.
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• Geographic profiling is a specific technique designed to
locate an offender’s residence or ‘anchor point’, based on
the analysis of his or her crimes from a spatial and temporal
perspective. It is based on the analysis of the locations of a
connected series of offences, the characteristics of the
neighbourhoods in which they have occurred and, where
available, the behavioural analysis/psychological profile of
the offender.
• The National Forensic Specialist Advisers provide advice
on the effectiveness and scope of forensic evidence from
both a strategic and tactical level in support of serious crime
investigations within the UK.
• The National Injuries Database (NID) supports and
advises serious crime investigations on the analysis and
interpretation of wounds and weapon recognition. The NID
focuses mainly on victims’ injuries and is used as a reference
tool to identify comparable cases. This enables the
establishment of a possible cause for a victim's unknown
wound. It can also show specific injury patterns caused by
identified weapons. The NID is linked to the Serious, Sexual
Assault and Attempted Murders Database. 
• The Serious Crime Analysis Section (SCAS) can help
identify possible cases committed by the same offender,
lines of enquiry and investigative priorities based on
statistical probabilities and lists of possible suspect
populations. SCAS analysts work closely with each
investigation and ensure reports are operationally pertinent
and delivered in a timely manner by setting specific terms
of reference.
• Missing Persons Bureau (MPB) acts as the centre for the
exchange of information connected with the search for
missing persons nationally and internationally. It often works
closely in partnership with the Missing People Charity under
the National Protocol Agreement and has historically focused
on cross-matching missing persons with unidentified persons
for operational purposes. The MPB also provides investigative
support and access to specialist advice. 
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Uniform Operational Support provides support and advice in
relation to specialist areas of uniform operational policing. This
operational support (eg, planning and debriefs) includes uniform
policing of incidents and events. It can offer a rapid response for
the Police Service to both national and international pre-planned
and spontaneous events in the areas of public order, police use of
firearms and disaster/incident management.
POLKA
The Police Online Knowledge Area (POLKA) is an online
collaboration platform provided by the NPIA for its staff and
wider policing community. It offers a new, efficient way of
working that simplifies the sharing of knowledge and practice.
Groups of users, known as communities, can share, discuss and
collaborate on a variety of information or documents through 
a range of technologies such as blogs, discussion forums and
document libraries. https://www.polka.pnn.police.uk
National Policing Improvement Agency, Research, Analysis
and Information Unit. 
The Research, Analysis and Information Unit (RAI) works in
conjunction with a number of units across the NPIA, the Home
Office and ACPO. The Unit has an ongoing research programme
which aims to identify and conduct research that will help to
improve policing in the UK. Part of this programme of research
focuses on undertaking projects to help improve the ability of the
Police Service to deal with problems associated with investigating
crime. The results of the research are distributed to the Police
Service through the PIU, training and development and through
NPIA publications. In addition, the RAI can provide information
on existing literature that might be helpful to forces.
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Investigative
Strategies
This section outlines strategies to assist investigators
to structure, plan, conduct and manage an
investigation. Each investigation presents its own
opportunities and difficulties. The strategies will not,
therefore, apply to every investigation and the
investigator must decide which are suitable and
proportionate to use in each individual enquiry. Some
of the strategies reflect those already set out in ACPO
(2006) Murder Investigation Manual (MIM), 
but can be
adapted for use in any type of investigation. The
overall planning of an investigation is the responsibility
of the investigating officer; investigative strategies
provide the means by which the plan is achieved.

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6: Investigative Strategies
Contents
6.1
Developing an Investigative Strategy
111
6.2
Scene Strategy
112
6.2.1 Identifying Scenes
113
6.2.2 Securing Scenes
113
6.2.3 Scene Examination
115
6.2.4 Further Crime Scene Considerations
116
6.3
Forensic Strategy
116
6.4
Search Strategy
118
6.4.1 The Legal Powers for Search
118
6.4.2 Methods of Searching
119
6.4.3 Search Considerations
120
6.4.4 Further Advice
121
6.5
Victim and Witness Strategy
121
6.5.1 Fast-Track Interviews
122
6.5.2 Conducting an Initial Risk Assessment
123
6.5.3 Witness Assessment
124
6.5.4 Witness Support
126
6.5.5 Victim/Witness as a Scene
127
6.5.6 Witness Interviewing
129
6.5.7 Welfare Issues
131
6.5.8 Witness Protection
131
6.5.9 Witnesses Who Refuse to Make Statements
131
6.5.10 Reluctant Witness Procedures
132
6.5.11 Further Advice
132
6.6
Intelligence Strategy
132
6.6.1 Intelligence Sources
133
6.6.2 Intelligence Evaluation
133
6.6.3 Analytical Support
134
6.6.4 Standard Analytical Products
134
6.7
Passive Data Generating Strategy
134
6.7.1 Further Advice
136
6.8
Trace/Interview/Eliminate (TIE) Strategy
136
6.8.1 Constructing a TIE Category
137
6.8.2 Populating a TIE Category
137
6.8.3 Prioritising TIE Categories
138
6.8.4 Suspect Parameters
138
6.8.5 Time Parameters
139
6.8.6 Elimination Criteria
139
6.8.7 Conducting TIE Enquiries
140
6.8.8 Financial Investigation
142
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6: Investigative Strategies
Contents
6.9
Communications Strategy
145
6.9.1
Internal Communications
145
6.9.2
Media Strategy
147
6.10 Covert Policing Strategy
151
6.11 Suspect Strategy
152
6.11.1 Arrest
152
6.11.2 Power of Arrest
153
6.11.3 Timing an Arrest
153
6.11.4 Searches 154
6.11.5 Planning an Arrest

154
6.11.6 Pre-Arrest Briefings
155
6.11.7 Post Arrest
156
6.11.8 The Identification of a Suspect
156
6.11.9 Voice Identification 
159
6.11.10 Suspect Interviews
159
6.11.11 Pre-Interview Briefing (Disclosure)
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6: Investigative Strategies
An investigative action can be defined as any activity which, if
6.1 Developing
pursued, is likely to establish significant facts, preserve material or
an Investigative
lead to the resolution of the investigation. There are two distinct
Strategy
types of investigative action. The first is a range of actions that are
intended as a general trawl for information. These can be undertaken
in any investigation irrespective of the circumstances of the case, but
are most likely to occur in the early stages of an investigation when
the information about the offence is often vague. Examples of these
activities will include:
• Crime scene examination; 
• Victim or witness interviews; 
• Media appeal; 
• House-to-house; 
• Area search; 
• Intelligence searches. 
The second range of actions relates to specific lines of enquiry that
have been generated during the investigation. These can occur at
any time and include: 
• Tracing a named suspect; 
• Identifying and locating potential witnesses to interview; 
• Pursuing significant information that requires further investigation. 
• Tasking CHIS. 
These enquiries differ from the first type because they are 
evidence-specific, and some information about the crime is needed
in order to identify the most appropriate action. 
During the initial investigative phase a range of actions will be
conducted. At this point many will be determined by the
circumstances of the allegation, but will be mainly concerned with:
• Obtaining initial accounts from victim(s) and witnesses; 
• Locating and securing material (eg, CCTV footage); 
• Identifying and preserving scenes or routes to and from scenes; 
• Arresting the offender(s).
Investigators must consider a number of issues when developing
investigative strategies. First and foremost are the legal and ethical
considerations relating to the conduct of any investigative action,
see 3 The Legal Framework. They must also prioritise and determine
the proportionality of the investigative response in accordance with
force policies.
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To develop an investigative strategy, the investigator must use their
knowledge and experience to decide which investigative actions are
the most appropriate in the circumstances.
The purpose of the strategy is to: 
• Identify the most appropriate line of enquiry to pursue; 
• Determine the objective of pursuing a particular line of enquiry; 
• Identify the investigative action(s) necessary to efficiently
achieve that objective taking into account resources, priorities
and proportionality; 
• Conduct the investigative action and gather the maximum
amount of material which may generate further lines 
of enquiry. 
The final decision about which investigative action to undertake
must be driven by the investigation itself and not just by completing
a checklist. 
The management of a crime scene will impact on the quality,
6.2 Scene Strategy
quantity and integrity of the material gathered. The identification 
of a crime scene is, therefore, a priority for the investigator as it 
may contain vital material which will influence the outcome of 
the investigation.
Once investigators have identified a scene, they should apply the
investigative mindset to make an initial assessment of its potential
to provide material, see 5.3 The Investigative Mindset. This
assessment and the subsequent formulation of a scene strategy
should have due regard to forensic strategy considerations, see
6.3 Forensic Strategy. Undue delay or failure to consider forensic
issues at this stage may lead to valuable material being
contaminated, overlooked or lost. This is usually referred to as the
Golden Hour, see 4.2.2 The Material Gathered by the Police. 
The extent to which investigators are responsible for managing
a crime scene and developing crime scene strategies is influenced
by the complexity or seriousness of the investigation, and local
force policy. 
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When gathering the material, investigators should liaise with crime
scene investigators (CSIs) and crime scene managers (CSMs) to
ensure that they use the most appropriate method of recovery. 
6.2.1 Identifying Scenes 
The crime scene can present itself in a number of ways and may not
be immediately obvious that it is a crime scene to either the
investigator or initial attending officers. This may include: 
• The victim; 
• Witnesses; 
• Routes to and from the scene; 
• The suspect; 
• Weapons (including live and spent ammunition); 
• The suspect’s home address or other premises; 
• Vehicles (including boats and caravans); 
• Dump sites (including victim, clothing, weapons or 
stolen property).
Often the scene of the offence will be relatively easy to identify 
and should, therefore, be considered a fast-track action. 
See 4.4.2 Initial Investigation. The victim or witnesses to the
offence will usually be able to tell investigators precisely where 
and how the offence was committed. This will enable investigators
to preserve the scene at the earliest opportunity and to recover the
best possible material in a manner which preserves its integrity. 
6.2.2 Securing Scenes 
The purpose of securing a scene is to maintain the integrity and
provenance of any material which may be recovered from it.
This simple and important action will reduce the opportunities for
the material to become contaminated or inadvertently cross-
contaminated. See Locard’s Principle overleaf.
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The techniques of crime scene management are based on
‘Locard’s Principle’ of exchange, which states that: 
Anyone who enters the scene both takes something of
the scene with them and leaves something of themselves
behind.
This means that every contact has the potential to leave a trace
however miniscule. Such traces are usually: 
• Fingerprints; 
• DNA; 
• Fibres; 
• Footwear marks.
These traces provide valuable material that can link a suspect to
the crime. The techniques for recovering this material are highly
specialised and CSIs have the necessary training and equipment
to carry them out. 
There are a number of methods that the investigator can use to
secure and manage a crime scene. These include: 
• Using tape to prevent access to or from the scene; 
• Deploying officers to guard the scene (care should be taken to
ensure that officers only attend individual scenes in order to
prevent cross-contamination); 
• Using vehicles as barriers to prevent entry; 
• Road blocks to protect wider scenes; 
• Temporary fencing; 
• Road diversions; 
• Ensuring that persons entering the scene are wearing suitable
protective clothing to prevent contamination of the scene and 
to ensure that they are protected from any hazards present; 
• Logging those who enter and leave the scene. 
The investigator should seek advice from CSIs or other suitably
qualified experts to determine the appropriate level and method of
protection required. This may include covering or lighting the scene
and identifying and protecting access routes to or from the scene. 
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Risks to the scene which have to be managed include: 
• Contamination of the scene by items being taken into or from the
scene, or cross-contamination by transference between scenes; 
• Damage being caused to the scene or material by exposure to
the elements; 
• Microbiological activity causing decay to material; 
• Animal disturbance; 
• The effect of time delay on certain material types. 
6.2.3 Scene Examination 
The recovery of material should only be undertaken by an individual
who is trained to perform this role. In some priority and volume crime
investigations this may be the initial investigator, CSI or other forensic
specialist. If an investigator has any doubts regarding appropriate
recovery and preservation techniques, they should obtain advice from
a CSI or CSM.
Scenes should be examined using a structured approach determined
by the parameters and requirements of the investigation. This should
be specific where required, but flexible enough to allow the facts to
become apparent through methodical examination techniques. The
scene strategy should be developed in consultation with the forensic
management team comprising the SIO, CSM, Exhibits Officer and
Specialist Adviser from the forensic supplier. 
The investigator must be conversant with all the material that has
been recovered from the scene. They need to recognise why it
has been recovered and its potential evidential value. In volume
crime investigations this may only amount to a few items or
exhibits. Advice and guidance regarding exhibit handling and
storage can be obtained from CSIs and CSMs. Investigators should
be aware of the information a forensic examination can provide.
This includes confirming or eliminating the presence of the following
at a crime scene or other location: 
• Victim(s); 
• Suspect(s); 
• Weapon(s); 
• Substance(s); 
• Other object(s). 
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This is achieved by identifying a range of items: 
• Physical (fingerprints or fibres); 
• Biological (blood, semen, saliva); 
• Chemical (drugs); 
• Other substances (firearms discharge residue, glass, petroleum)
in or on a crime scene or individual. 
Investigators must also understand what scientific examinations
cannot achieve.
6.2.4 Further Crime Scene Considerations 
MIM provides further information which investigators should
consider. This includes: 
• Prioritising the order of recovery of physical material (eg, blood,
fingerprints, hairs, fibres, fluids and documents); 
• Ensuring the integrity of all scenes and preventing 
cross-contamination;
• Understanding the need for and frequency of crime scene
conferences;
• Determining which scene should be given priority in multi-scene
investigations;
• Establishing who has examining precedence at the scene, eg,
CSI, pathologist, biologist, fire investigator or forensic scientists.
This must be coordinated by the IO or SIO who will maintain
overall responsibility for deciding the order of precedence. They
can be assisted by a CSM at an individual scene or a coordinator
at a multi-scene investigation. 
For further information on crime scene management, see MIM
Section 9 Crime Scene Management. For further information on
exhibit management, see 7.7.1 Exhibit Management.
The use of a forensic strategy will enable the investigator to
6.3 Forensic
maximise the potential of any material recovered during the crime
Strategy
scene examination phase. 
MIM lists the following range of investigative options that can be
developed by using forensic examination. They apply equally to
any investigation. 
• Clarification of the circumstances – providing movements of
victims and suspects, establishing crime scenes and attack sites,
and challenging assumptions. 
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• Elimination of suspects – through partial DNA or partial palm prints.
• Forensic intelligence – providing potential links at scenes, DNA
profiles from body fluids.
• Inceptive evidence – the identification of an unknown person or fact,
for example, identification through fingerprints or via DNA deposits.
• Context – once the evidence has been obtained, establishing where
it fits in the context of the whole investigation or examinations.
• Clarification of the sequence of events – through, for example,
analysis of blood distribution, or the use of fire investigation units.
• Corroboration – including independent confirmation of
circumstances, critical fact or witness testimony and evidence of
the culpability of a suspect.
The use of forensics may also provide the investigator with
information that can be used during interview to test the reliability of
an account. It may also assist them in prioritising lines of enquiry or
submitting particular items for examination.
The investigator should carefully examine forensic results to
determine their meaning. If the significance of the information
cannot be established, they should seek advice and clarification from
a CSM, forensic liaison or the forensic provider.
In serious or complex investigations the number of items or exhibits
may be substantial and will require the appointment of an exhibits
officer. The exhibits officer’s responsibilities include liaison with CSIs
and forensic science providers to ensure that the recovery, handling,
storage and submission of all relevant exhibits is undertaken. The
exhibits officer must maintain a close working relationship with the
investigating officer to ensure that they are aware of all
developments in the investigation. In addition, information
concerning submissions and the results of forensic examinations
should be brought to the investigating officer’s attention.
Additional advice and assistance can be obtained from CSIs, CSMs,
force forensic advisers and the Forensic Search Advisery Group via
the NPIA SOC.
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Most investigations require a search to be conducted. The nature
6.4 Search Strategy
and circumstances of the investigation will indicate the type of
search required, together with the number of resources and/or
specialists needed. The method or methods which the investigators
decide to employ will depend on the specific objective of the search
and its location. 
Searches can be conducted to identify and locate the following
sources of material: 
• Crime scenes; 
• Victims, witnesses or suspects; 
• Physical material – weapons, stolen or discarded property, 
CCTV videotape or other media storage, documents; 
• Scientific material – biological and chemical, eg, fingerprints,
blood, semen, saliva, hair, firearms discharge residue, drugs; 
• Escape routes; 
• Hides, storage or deposit sites; 
• Electronic media stored within IT systems or
telecommunications equipment; 
• Passive data generators such as CCTV. 
6.4.1 The Legal Powers for Search 
While the majority of searches of premises can only be carried out
with consent, investigators will rarely face objections from victims or
witnesses. They should, however, be prepared to explain the reasons
for carrying out the search if asked. Search powers to arrest people
also apply.
Investigators should consider the following: 
• Is there lawful access to the property? 
• Is a search warrant required? 
• Do sections 17, 18 and 32 PACE apply? 
Records must be made of the: 
• Areas searched and the level of intrusion; 
• Identification of all individuals conducting the search; 
• Search techniques, equipment used and search duration; 
• Significant material found at location. 
All material recovered during searches should be handled
appropriately, labelled and packaged in accordance with force
instructions. Where it is not possible to complete a search in one
continuous period, consideration should be given to preserving and
protecting the scene. 
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6.4.2 Methods of Searching 
Search methods employed by investigators will vary according to the
type of investigation being conducted, but all searches must be
carried out thoroughly. The method or methods used will depend on
the primary objective of the search. The location and subject of the
search will also determine the most applicable search method. For
example, the search of a known drug dealer’s premises may be more
intrusive than that of a juvenile shoplifter’s house search. The
purpose of searches conducted during volume crime investigations
will usually be to locate: 
• Crime scenes; 
• Stolen or abandoned property; 
• Suspects; 
• Concealed drugs. 
The minimum standard required for a search of premises is an 
‘open door search’. This entails opening all doors and searching all
rooms, outhouses, sheds, lofts, cupboards, wardrobes and drawers.
Searches of premises can be conducted using the, ‘side to side and
up and down’ method (which entails searching from the ceiling to
the floor and from wall to wall). Searching a vehicle requires the
‘clean and dirty’ approach. This includes an examination of the
interior and exterior and areas such as the engine compartment,
wheel spaces and boot.
Other types of search include:
‘Hasty’ Searches
The term hasty is recognised and widely accepted in the field of
search and rescue. It should not be construed as lacking in
thoroughness or detail and should be part of an initial investigative
fast-track action. 
A hasty search is an initial visual check using available local resources.
These searches should be systematic and methodical. A record of the
nature and extent of the initial hasty search will assist the
formulation of any later search plans. 
The purpose of a hasty search is to make a rapid identification of
material likely to assist in an investigation. Consideration must be
given to the potential risk of damaging forensic opportunities. Hasty
searches are commonly used as a fast-track action during the Golden
Hour. Failure to carry out these searches could result in material being
lost, damaged or destroyed, to the detriment of the investigation. 
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Fully Managed Searches 
This type of search is intrusive and detailed and is conducted by
individuals who are licensed as trained and/or recognised by the Police
National Search Centre. The Police Search Adviser (PolSA) is responsible
for the conduct and management of the search but staff conducting
the search may require to be briefed by the investigator. Overall
management of the investigation is retained by the investigator.
Note: Officers who attend the Police National Search Centre (PNSC)
and receive training in all search-related matters, qualify at the
conclusion of this training as a PolSA. They can then advise
investigators on all aspects of searching.
6.4.3 Search Considerations 
Risk Assessment 
The early decisions on the level of searches to be undertaken are
subject to a risk assessment governed by the following critical factors: 
• The need to preserve life; 
• An immediate threat to life; 
• Immediate pursuit of a suspect; 
• The likelihood of destruction, damage or disposal of material –
caused by weather or outside interference with the material; 
• The likelihood that recovering the material will lead to a rapid
arrest of a suspect. 
Once the object of the search has been found, the power to search is
likely to cease, for example under section 17(4) PACE.
Prioritising Searches 
There are rare occasions when the need to conduct a physical search
conflicts with the requirement to conduct a forensic examination.
Any physical search will increase the potential risk of contaminating
the scene. As a rule the forensic search, undertaken by trained
specialists, should take precedence over the physical search. There
will be occasions, however, when the investigator is faced with one or
more of the critical factors. In these circumstances the search must
be conducted in such a manner as to minimise the contamination
risk, and record how this was achieved. Wherever possible, advice
should be sought from experts such as a CSI or CSM to identify the
most suitable method to employ. 
Where it is immediately obvious that the scene represents a serious or
major incident and there are no immediate risks to life or the material
within the scene, the initial attending officer should secure and protect
the scene, request assistance and inform a supervisor or senior officer.
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6.4.4 Further Advice 
Further information and assistance on search techniques and methods,
and expert advice can be obtained from the following sources: 
• ACPO (2006) Practice Advice on Search Management and
Procedures; 
• CSI and CSM;
• Forensic science liaison staff;
• PolSA; 
• Force computer crime specialists; 
• Force firearms units; 
• NPIA Specialist Operations Support; 
• ACPO (2006) Murder Investigation Manual (MIM);
• PACE Code B.
Victims and witnesses are a fundamental component of the criminal
6.5 Victim and
justice system. They provide the information, intelligence and
Witness Strategy
evidence to investigators which enables offenders to be brought to
justice. In order for the system to operate effectively, victims and
witnesses must have confidence in the criminal justice process. In
turn, the system must recognise the needs and concerns of victims
and witnesses and provide adequate information, support, protection
and reassurance to generate faith and trust in the legal processes. 
There is a distinct difference between the terms victim and witness. 
• A victim is defined as a person harmed by a crime, tort or other wrong.
• A witness is defined as one who sees, knows or vouches for
something. One who gives testimony under oath or
affirmation, in person, by oral or written deposition or by
affidavit. A witness must be legally competent to testify. 
Black’s Law Dictionary, Ninth Edition (2009) 
Despite the difference in definition, all victims are potential
witnesses. For the purpose of this strategy all references to witnesses
includes victims, unless it is specifically stated to the contrary. 
The detection of a large proportion of offences can be attributed to
information provided by the public. It is, therefore, important that
investigators recognise this and take active steps to identify and
locate witnesses at the earliest available opportunity. 
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Some witnesses may self-present or be self-evident, other witnesses
may be more difficult to identify and/or locate. Investigators should
consider various techniques to identify and locate witnesses. These
may include:
• Viewing CCTV;
• Media appeals, see 6.9.2 Media Strategy;
• House-to-house enquiries;
• Interviews with victims and other witnesses;
• Suspect interviews;
• Anniversary appeals.
The success of any investigation largely depends on the quality of
material that is obtained from victims, witnesses and suspects.
ACPO (2004) Practical Guide to Investigative Interviewing states: 
A major source of material in police investigations comes from
interviews with victims and witnesses. This should be accurate
and in as much detail as possible. It is the information
provided by witnesses and victims that may enable you to
validate or challenge a suspect’s version of events.
Witnesses should be interviewed in accordance with the PEACE
model of interviewing.
The manner in which investigators approach witnesses, from the
point of initial contact, during interviews and through to the
conclusion of any subsequent prosecution case, can have a
significant bearing on their perceptions of how the criminal justice
system operates. Inappropriate or ill-considered methods of dealing
with the witness may hamper the investigation and delay or prevent
the supply of relevant material which would assist the investigator. 
6.5.1 Fast-Track Interviews 
There may be occasions when it is necessary to conduct a fast-track
interview with a witness who possesses material which is likely to
rapidly progress the investigation and can result in: 
• The early identification or arrest of a suspect; 
• The recovery of material connected with the offence; 
• Preventing the imminent disposal or destruction of material
connected with the investigation; 
• Preventing the commission of other offences. 
In these circumstances the investigator has to consider the
immediate needs of the witness, who may require medical attention
or that a suitable adult be present. Common sense has to be applied
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and the interview should be limited to obtaining sufficient
information to immediately progress the enquiry. The circumstances
surrounding the fast-track interview should be recorded, and
permission obtained from medical staff if the witness is receiving
non-urgent attention.
Invariably, priority and volume crime investigations will not require
an explicit strategy. Nevertheless all investigators should be aware
of the anxiety and misapprehension that witnesses may feel when
they are exposed to the criminal justice processes. For many, this
will be the only time in their lives that they have been a victim or
witness and they may not understand how the criminal justice
system operates. They will require reassurance and information
throughout the process. Investigators, whether tasked with a
volume crime or major investigation, must recognise the individual
needs and concerns of witnesses.
6.5.2 Conducting an Initial Risk Assessment
Risk assessment commences the moment that the circumstances of
the crime are notified to the police and must continue throughout
the investigation. The potential risks should be established and
decisions made on how to minimise and manage them. Some of the
early risk assessment can be conducted by the call taker, who should
do the following:
• Prioritise the safety of the witness by providing safety, first aid or
other advice if appropriate; 
• Keep the victim fully updated of the deployment of officers; 
• If the suspect is still present at the scene, keep the caller on the
line as any background noise from a 999 call will automatically
be recorded and can be used as evidence as well as a means of
monitoring the incident; 
• If the suspect has left the scene, advise the caller to lock and
secure the premises and to return to the telephone. Obtain a full
description of the suspect and circulate it to officers in the area. 
The information provided can be passed to the initial investigators so
that they are fully informed and can continue assessing the risk on
arrival at the scene. Risks can include any or all of the following: 
• The physical health and welfare of the victim or witnesses; 
• The suspect(s), who may still be present or in the vicinity and
posing a threat; 
• Forensic or other relevant material which may be disposed of,
destroyed or damaged; 
• Risk to other potential victims or witnesses caused by the
commission of further offences. 
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Having identified the potential risks, investigators then have to
manage them. In the early stages of the investigation this may
include providing: 
• First aid or access to medical treatment; 
• Security and protection. 
The initial management of these risks will depend on the scale and
complexity of the investigation. In simple cases these risks will be
managed by one officer. 
Investigators should establish a working relationship with victims and
witnesses that recognises and understands their diverse social, cultural,
religious needs, and disability, for which reasonable adjustments are
required. They may be shocked or traumatised by events and have a
genuine fear of the consequences of providing information. Although
investigators need to provide adequate support, there will be
circumstances when it will be appropriate to obtain an early account to
enable the investigation to progress. By adopting a calm reassuring
interview style, investigators can establish the main points of what victims
and witnesses know about the incident. Suitable care and support can
then be provided prior to an in-depth interview, see 6.5.7 Welfare Issues.
6.5.3 Witness Assessment 
The investigator is required to make an initial assessment of the
witness prior to conducting any interview. This assessment is
necessary in order to determine whether the witness can be
categorised as being: 
• Vulnerable by reason of 
– being under 18 years of age
– mental disorder 
– significant impairment of intelligence and social functioning 
– physical disability 
– physical disorder; 
• Intimidated by reason of 
– age (elderly and/or frail)
– social, cultural or ethnic background 
– domestic and employment circumstances 
– religious and other beliefs
– political opinions 
– behaviour towards the witness on the part of the accused,
members of the accused’s family or associates of the accused 
– any other person who is likely to be an accused or witness in
the proceedings. 
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Complainants to sexual offences are defined as intimidated. Upon
implementation of sections 98–103 Coroners and Justice Act 2009,
witnesses to knife and gun crime are also defined as intimidated.
MoJ (2011) Achieving Best Evidence in Criminal Proceedings
contains advice and guidance for investigators tasked with
interviewing vulnerable, intimidated and significant witnesses. It also
provides advice on conducting the witness assessment, and this
should include their:
• Availability to attend court;
• Need for specific assistance;
• Need for support as a vulnerable or intimidated witness.
In addition, the assessment should include details of any information
provided to the witness under local agreements.
Further guidance on special measures and witness care for
vulnerable and intimidated witnesses is contained in MoJ (2011)
Achieving Best Evidence in Criminal Proceedings, 
available at
http://www.justice.gov.uk/guidance/docs/achieving-best-
evidence-criminal-proceedings.pdf

ACPO (2010) Advice on the Structure of Visually Recorded
Witness Interviews 
is also available to support interviewers.
Key or significant witnesses are defined in MIM as those who: 
…may have been, or claim to have been, an eye witness or
a witness to the immediate event in some other way; or
those who stand in a particular relationship to the victim or
have a central position in the enquiry.
The video recording of key or significant witness interviews should be
considered in cases of: 
• Murder; 
• Manslaughter; 
• Road death; 
• Serious physical assault (section 18 Offences Against the
Person Act); 
• Sexual assault; 
• Kidnap; 
• Robberies in which firearms are involved; 
• Any criminal attempts or conspiracies in relation to the above
listed offences. 
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If a police officer has witnessed any of the above offences, 
they should also be considered to be a significant witness. 
An investigator can also consider video or audio recording significant
witness interviews in any other serious case where it may be helpful
to the case. For further information and guidance on conducting
interviews with key or significant witnesses, see ACPO (2004)
Practical Guide to Investigative Interviewing. 

6.5.4 Witness Support 
Invariably, all witnesses will require a degree of support during any
investigation. In some circumstances this support may be provided by
verbal reassurances from the investigator, family members or close friends
in accordance with the Victim’s Charter. In more serious investigations
support may also be provided by deploying specially trained officers.
There are also a number of community and charitable organisations that
provide valuable services to witnesses. Their services can assist the
investigator to support a witness and include: 
• Family Liaison Officers (FLO); 
• Sexual Offence Liaison Officers (SOLO/STO); 
• Domestic violence officers and coordinators; 
• Victim support schemes – including the Witness Service; 
• Sexual assault referral centres (SARC); 
• Social services; 
• Health service; 
• Race equality councils; 
• Gay and lesbian support groups; 
• Religious organisations or groups;
• Neighbourhood Policing Officers and Police Community 
Support Officers.
Investigators must recognise the impact that being a witness to a
crime or event can have on an individual. They may feel shocked,
traumatised, vulnerable or intimidated by the experience. 
Adopting a calm reassuring approach and providing information
about organisations that give support can assist in alleviating the
witness’s anxiety and fear. As the case progresses, the witness may
receive additional help and support from the Witness Service. This is
run by volunteers from Victim Support, and offers:
• Information on what takes place at court; 
• Emotional support and confidential advice; 
• A familiarisation visit to the court; 
• Court room support for the witness. 
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Other useful information is contained on the following websites:
http://www.justice.gov.uk/guidance/victims-witnesses/working-
with-victims-witnesses.htm
http://www.victimsupport.org.uk
6.5.5 Victim/Witness as a Scene 
In cases of physical or sexual assault the investigator has an early
opportunity to obtain forensic material from the victim or their clothing.
This material may include body fluids or other cellular or fibre transfers.
In such cases the investigator must balance the victim’s medical and
welfare needs with the recovery of uncontaminated material for the
investigation. The victim may not recognise or understand the
significance of the requests for this material. Assistance from specially
trained officers and the use of specialist centres, where available, will
enable the investigator to recover material, while ensuring that victims
receive appropriate support and counselling. 
The investigator and the specialist officer need to maintain close
contact. This can be achieved by regular meetings to brief and debrief
each other. If a specialist officer is deployed to assist an investigator,
an accurate record must be maintained on the crime report, policy log
or file outlining the specific role of the specialist officer. 
Investigators must recognise that police officers who are witnesses
are not immune to similar fears and anxieties, especially when they
are witnesses to traumatic or unusual events. Force welfare
departments can be contacted to provide advice and guidance to
officers in these circumstances. 
In the majority of cases investigators can support witnesses by
providing them with relevant information about the progress of the
investigation and of any significant developments. Witnesses should
always be provided with the following details: 
• The name of the investigating officer; 
• Contact details for the investigating officer; 
• Crime or incident reference number. 
When a suspect is identified or arrested, the witness should be
informed and kept updated about court appearances and
whether remands are in custody or on bail. If on bail, the witness
should be made aware of any conditions that have been imposed
on the suspect. 
The Victim Personal Statement can be used to inform the
prosecution about the impact of the offence on the victim’s life. 
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The Victim Personal Statement Scheme (VPS)
The VPS gives victims an opportunity to tell the criminal justice
agencies and the magistrate or the judge about the effect a
crime has had on their lives.
It also helps the criminal justice agencies to understand fully the
impact that the crime has had on the victim so that they can
make decisions about the case.
The VPS is optional. No pressure should be put on victims to
make one if they do not want to. However, it is important that
the victim understands the benefit of making one.
A VPS is a statement written in the victim’s own words. It is
different to the witness statement, which is a written or video-
recorded account of what happened to the victim. The VPS can
be taken at the same time as the witness statement, but it can
also be taken at a later stage.
It can be used to:
• Explain the effect that the crime is having (or has had) on
the victim’s life physically, emotionally, financially or in
another way;
• Express concerns about intimidation from the suspect;
• Express concerns about the suspect being granted bail;
• Ask for support from Victim Support;
• Request compensation (you, as a police officer will also need
to complete form MG19).
Criminal Justice System: Victim Personal Statements: 
A guide for police officers, investigators and 
criminal justice practitioners
Further information on witness support can be obtained from
http://www.cps.gov.uk
Further information on support available to victims can be 
obtained from:
• ACPO/NPIA Practice Advice and Guidance; 
• http://www.homeoffice.gov.uk/crime/ which includes the New
Deal for Victims and Witnesses National Strategy and mini sites
dedicated to different crimes.
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6.5.6 Witness Interviewing 
Interviews are a means by which an investigator can both obtain 
and impart information. The investigator must establish trust with
the interviewee. Many witnesses fear the consequences of providing
information. They, therefore, need to be able to trust the
competence of the investigator to deal appropriately with the
information they provide. If they have confidence in the interviewer,
they are more likely to provide them with a full and accurate account.
Witnesses have a right to expect that they will be listened to and will
receive fair treatment. 
CJS (2011) Achieving Best Evidence in Criminal Proceedings and
ACPO (2004) Practical Guide to Investigative Interviewing
provide information and practical advice to investigators in relation
to all aspects of investigative interviewing. 
The PEACE model is the nationally accepted method of interviewing
victims, witnesses and suspects. PEACE stands for: 
– Planning and Preparation; 
– Engage and Explain; 
– Account Clarification and Challenge; 
– Closure; 
– Evaluation. 
The skills needed by investigators using the PEACE model are 
as follows.
• Planning and preparation – assembling the facts, knowledge of
the location and circumstances of the offence, knowledge of the
interviewee if practical, being methodical, legal knowledge and
considering the timing, duration and location to conduct the
interview. Selection of the interviewer and the timing of breaks. 
• Establishing a rapport – considering how to approach the
interviewee, being aware of their needs, culture and background,
language, displaying flexibility, approachability, not prejudging,
avoiding being over officious and personal bias. 
• Listening skills – developing the ability to listen actively,
displaying empathy, consideration and tolerance. Using silence
to obtain further information. 
• Questioning skills – asking the right questions at the right time,
use of appropriate language and perseverance. 
ACPO (2004) Practical Guide to Investigative Interviewing also
defines the different tiers of interviewers who have received specialist
training on interviewing specific categories of witness. These officers
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can assist investigators to plan, conduct and manage the
interviewing process, thereby obtaining the best possible evidence
from witnesses.
NPIA (2009) Briefing Paper: National Investigative
Interviewing Strategy 
lists the seven principles of investigative
interviewing. Investigators should adhere to these principles to
ensure any evidence obtained during an interview is admissible in
any subsequent proceedings.
The aim of investigative interviewing is to obtain accurate and
reliable accounts from victims, witnesses or suspects about
matters under police investigation.
Investigators must act fairly when questioning victims, witnesses
or suspects. Vulnerable people must be treated with particular
consideration at all times.
Investigative interviewing should be approached with an
investigative mindset. Accounts obtained from the person who is
being interviewed should always be tested against what the
interviewer already knows or what can reasonably be established.
When conducting an interview, investigators are free to ask a wide
range of questions in order to obtain material which may assist 
an investigation.
Investigators should recognise the positive impact of an early
admission in the context of the criminal justice system.
Investigators are not bound to accept the first answer given.
Questioning is not unfair merely because it is persistent.
Even when the right of silence is exercised by a suspect,
investigators have a responsibility to put questions to them.
The interview process should not conclude on provision of the
necessary account or statement.
Investigators should maintain a professional relationship with the
witness throughout the investigation, keeping them updated of its
progress. This should include:
• What will happen during the investigation even where the
matter remains undetected?
• What will occur if an offender is arrested and pleads guilty or 
not guilty?
• Contact details of the officer in charge of the investigation and
any known reference numbers (eg, crime number).
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6.5.7 Welfare Issues
Investigators tasked with interviewing a witness should consider
the welfare needs of the witness throughout. Factors to consider in
this are:
• Age and mental capacity of the witness – legal requirements
dictate how material can be obtained from individuals;
• The emotional health and welfare of the witness;
• The language skills of the witness, interpreters should be used in
accordance with ACPO policy and local guidelines;
• How to prevent further offences from occurring such as intimidation.
Third-party support may be beneficial to some witnesses, provided
that they are unconnected with the investigation.
6.5.8 Witness Protection 
Where it is felt that a witness may be intimidated, investigators,
working in conjunction with the CPS, can develop a witness care
strategy designed to protect the witness from intimidation or
harassment. This can include protecting the identity of the witness
during the investigation, the early stages of the prosecution process
and, in certain exceptional circumstances, through the trial itself.
There is a range of local measures which investigators can employ to
improve security and provide protection. These include:
• The provision of a ‘Homelink’ alarm system; 
• Upgrading security at the home address; 
• Temporary relocation; 
• Entries on briefing and intelligence systems. 
Investigators can obtain assistance with these interim measures from
local crime reduction advisers and neighbourhood policing teams.
Some local authorities also provide access to resources to assist with
witness protection issues. 
6.5.9 Witnesses Who Refuse to Make Statements 
Investigators should bring to the attention of the CPS details of any
witnesses who have been interviewed and who have refused to make
a statement. The investigator should outline the details of the
material the witness has provided and copies of any notes made or
statements compiled which the witness has refused to sign. The
investigator should provide the CPS with all the information provided
by the witness which may account for their refusal to provide a
statement. This may become crucial if the witness is later called as a
defence witness. 
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6.5.10 Reluctant Witness Procedures 
Where a victim has been interviewed during an investigation and the
investigator has been made aware that the witness is reluctant to
attend court to give evidence, early liaison with the CPS may enable
the prosecutor to apply for a witness summons prior to the
commencement of the proceedings, to secure their attendance. The
No Witness, No Justice care project has created joint CPS and police
Witness Care Units (WCU). WCUs are responsible in conjunction with
the investigator for providing specific support for witnesses.
6.5.11 Further Advice 
For further information and practical advice in relation to all aspects
of witness issues, see
http://www.justice.gov.uk/guidance/docs/achieving-best-
evidence-criminal-proceedings.pdf

Guidance notes for the provision of therapy for child witnesses can
be found on the CPS website at http://www.cps.gov.uk
The investigator will not usually need to set an intelligence strategy
6.6 Intelligence
in volume crime investigations. The force and local tasking and
Strategy
co-ordination processes will have defined intelligence requirements
based on the strategic assessments as set out in NIM. The
intelligence strategy will direct the sourcing and collection of all
information relevant to the investigation. Volume crime investigators
should be aware of the intelligence sources available to them at local
and force level, and how they can be used to assist to develop
intelligence. These sources include analysts, neighbourhood policing
officers, source management units and IT systems. In major and
serious investigations the creation of an intelligence cell could be
considered. Information and advice regarding intelligence cells is
contained within MIM and MIRSAP. 
Investigators must know what sources of intelligence are available
to them and how those sources can be tasked and used. The
intelligence strategy will focus on the collection and development
of material that will assist the investigation. Additionally,
investigators have to recognise that every investigation is unique
and potentially generates intelligence which can be used in other
policing activities.
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6.6.1 Intelligence Sources 
There are many sources of information available to the
investigator. Access to some of these sources is freely available,
while access to others is controlled by legislation. As a result,
deployment of them depends on the nature and complexity of the
investigation and the necessity and proportionality of their use.
For further information on the legislation covering the use and
deployment of intelligence sources, see 3.10 Regulation of
Investigatory Powers Act 2000. 
Investigators should take
advantage of all intelligence sources throughout the course of any
investigation. In some investigations developing intelligence will
be considered as a fast-track action.
Intelligence sources can include: 
• Police National Computer (PNC), including QUEST and VODS,
Impact Nominal Index, IDENT 1; 
• Local intelligence databases, eg, force computerised incident
handling systems, crime recording systems, force and 
local intelligence systems, Police Informant Management
System (PIMS);
• Police National Database (PND); 
• Automated billing systems; 
• Covert listening devices, probes and tracking devices; 
• Human intelligence sources including, victims, witnesses,
suspects, colleagues such as local and field intelligence officers,
community sources including community and race advisers, local
councillors, religious leaders and members of the community; 
• Covert Human Intelligence Sources (CHIS) and 
undercover officers;
• Physical evidence sources such as information about physical
conditions obtained from the scene of a crime. 
6.6.2 Intelligence Evaluation 
Information from intelligence sources is subject to evaluation to
check its reliability before being recorded in intelligence systems.
Evaluation must not be influenced by personal feelings but must be
based on professional judgement. Its value must not be exaggerated
in order to ensure action is taken. Investigators recording intelligence
on reports are personally responsible for ensuring the accuracy and
unbiased evaluation of the material, based on their knowledge of the
circumstances prevailing at the time. Each piece of intelligence
should be separately evaluated using the 5x5x5 system. Intelligence
material is subject to the rules of disclosure outlined within the CPIA. 
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6.6.3 Analytical Support
Once material has been collected and evaluated, its interpretation
and assessment should be undertaken by a trained analyst. The
analyst will be able to identify information gaps and any material
which requires corroboration. This process will assist the development
of an intelligence strategy, and enable the investigator to continually
review the progress of the investigation. This will include: 
• Assessing the progress of lines of enquiry; 
• Identifying new lines of enquiry to be pursued; 
• Identifying specific elements of the enquiry which would benefit
from further development. 
6.6.4 Standard Analytical Products 
Tasking the analyst properly requires the investigator to have a basic
understanding of the techniques used by the analyst. The analytical
product will depend on the initial tasking and will make use of the
standard analytical techniques as defined in NIM, such as Crime
Pattern Analysis and Network Analysis. In major and serious
investigations techniques might also include Comparative Case
Analysis and Major Incident Analysis. 
The product will be in the form of a written report or briefing and will
identify key findings and intelligence gaps, and make
recommendations to the investigator based on the analysis. It may
be supported graphically by a chart or map. 
For further information on the use of analysts within an investigation,
see ACPO (2005) Major Incident Analysis Manual and ACPO
(2008) Practice Advice on Analysis.

Passive Data Generators are automated systems that gather and
6.7 Passive
collate information for various purposes. These may include: 
Data Generating
Strategy

• Automated security CCTV systems (not including permanently
monitored systems); 
• Automated billing systems, including banking and
telecommunications billing; 
• Automated voice recording systems, 999 system, financial and
insurance call centres; 
• Automated access systems, entry and exit recording systems; 
• Customer records, subscriber information.
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These systems can generate large quantities of data, which is
periodically downloaded, archived or deleted. Fast-track action is,
therefore, required to ensure that these sources are preserved
and retained. 
Access to some of the material which these systems generate is
governed by legislation such as RIPA or PACE. Additionally,
investigators must be aware of the agreed protocols, eg, the
Communication Service Providers (CSPs) have agreed protocols
which permit investigators to preserve and access call data records.
To ensure consistency and conformity with these protocols, identified
individuals have been trained and accredited to act as Single Points
of Contact (SPoC) for each force. Investigators requiring information
and advice about obtaining material from CSPs are advised to make
early contact with the SPoC. 
Passive data generators can create volumes of material and, when
defining the strategy, investigators must consider: 
• Whether the request for information is proportionate to the
circumstances; 
• Precisely what they are seeking to achieve from the material; 
• The volume of data that may be generated; 
• When the data is provided what they are going to do with it; 
• Time considerations – the length of time it will take to produce
the data, the format it will be available in, how long will it take to
produce, how long will it take the investigators to analyse; 
• Resources – the likely costs in financial, human and technical terms;
• Analysis – deciding who will conduct the analysis, whether the
investigation has the capacity or capability to be effectively
managed, whether the staff are suitably knowledgeable to
understand the material; 
• The value that the material will add to the investigation. 
When access to material created by passive data generators is
obtained, investigators must know how that material was created.
The integrity and accuracy of this material will have to be
demonstrated if it is to be used as evidence. In certain circumstances
it may be necessary to seek expert advice or to conduct a forensic
examination of the material in order to confirm its authenticity
and accuracy. 
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6.7.1 Further Advice 
The telecommunications industry changes rapidly. Retail products
and the technology that drives them are constantly changing. 
In developing a telecommunications strategy the investigator
should be aware of what material can be provided by the CSP. 
This will contain details of:
• Time; 
• Date; 
• Duration; 
• Caller identity; 
• Receiver identity; 
• Location caller or receiver; 
• Types of apparatus used. 
In relation to:
• Voice calls; 
• Data calls; 
• Fax; 
• SMS (text) calls; 
• MMS (picture) calls; 
• Emails, chat rooms and other IT facilities.
Further advice and guidance for investigators on the retrieval of
intelligence that may be held on computers and portable IT systems
can be obtained from within force computer and IT units.
Information regarding access to banking records can be obtained
from force economic units. 
Additional information is available in ACPO (n.d.) Good Practice
Guide for Computer-Based Electronic Evidence 
or by contacting
the e-crime section of the Serious Organised Crime Agency (SOCA).
The term Trace/Interview/Eliminate (TIE) is taken from major
6.8 Trace/Interview/
incident investigation and is described in detail in MIM. A TIE
Eliminate (TIE)
strategy enables investigators to identify groups of people likely to
Strategy
include the offender. Enquiries can then be conducted to eliminate
those who cannot be the offender and to implicate those who can.
Further investigative effort can then be focused on those who are
implicated, with the intention of identifying the suspect.
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The term Trace/Interview/Eliminate first appeared in MIRSAP in
2005. Since then some forces have adopted different
terminology, eg, Trace/Implicate/Eliminate or Trace/Implicate/
Evaluate. These differences in terminology do not affect the
procedures to be followed when undertaking TIE enquiries. 
6.8.1 Constructing a TIE Category 
Investigators who are not familiar with this investigative technique
should seek the assistance of more experienced colleagues and
supervisors. A TIE strategy can be very resource intensive and
unless managed effectively has the potential to incorrectly eliminate
the offender.
A TIE category is a group of people sharing a common characteristic
which is likely to include the offender. The common characteristic on
which the group is based will depend on the circumstances of the
crime. TIE categories are typically based on those:
• With access to the scene at the time of the offence; 
• Living in, or associated with, a certain geographical area; 
• Associated with the victim; 
• With previous convictions for similar offences (usually known as
MO suspects); 
• With physical characteristics similar to the offender; 
• With access to certain types of vehicle. 
This is not an exhaustive list and the more that is known about the
circumstances of the crime, the greater the chances of constructing
an accurate TIE category. 
6.8.2 Populating a TIE Category 
Having decided which groups are likely to include the offender,
investigators must identify as many of the members of the group as
possible. In some cases this will be known with some degree of
certainty. For example, a check of company records which identifies
all employees could create the TIE category of ‘those employed in
the named premises’. In other cases the exact membership of the
group may be difficult to determine, for example, a TIE category for
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‘those visiting a named premises’. This may be more or less difficult
to determine depending on the type of premises, the number of
persons visiting and the number of access points. 
The following are useful ways of populating TIE categories: 
• Official records, such as membership lists, payrolls, electoral registers;
• Police intelligence databases; 
• Media appeals; 
• ‘Snowballing’ – this technique involves interviewing known
members of a TIE category to identify other members of the
group. Like a snowball rolling down hill, this technique can start
from a single point gathering additional material as it goes. 
Those who populate a TIE category are known as TIE subjects. 
6.8.3 Prioritising TIE Categories 
Sometimes the population of a TIE category is very large and it is not
possible to carry out enquires on every subject. Investigators may
simply want to start with those members who are most likely to be
the offender. In such cases it is possible to apply a number of filters
to the category according to the priorities chosen by the investigator.
These filters could include: 
• Proximity to the scene; 
• Date of last conviction of MO suspects; 
• Age (where the age of the suspect is not known, investigators
may wish to prioritise those who fall within the most likely age
range of offenders for that category of crime); 
• Sex (where the sex of the offender is not known, investigators
may wish to prioritise those who are of the sex which is most
likely to have committed the crime). 
6.8.4 Suspect Parameters 
Suspect parameters are the known characteristics of the offender
that can be used to implicate or eliminate those within a TIE
category. These can include: 
• Sex; 
• Age; 
• Physical characteristics; 
• Fingerprints; 
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• Forensic characteristics such as DNA, fibres, footmarks; 
• Ownership of a particular make or colour of vehicle; 
• Ownership of particular clothing. 
The value of these characteristics varies. A fingerprint or DNA is likely
to eliminate all but the offender, whereas knowing only the sex of
the offender is of limited assistance, although it still eliminates half
the population. 
Investigators should always consider setting parameters wider than
those suggested by the material to allow for a degree of error in
descriptions given by victims or witnesses. 
6.8.5 Time Parameters 
The timeframe within which a crime was committed is a useful way
of eliminating individuals from the TIE category. People may be able
to prove that they were elsewhere when the crime was committed. 
Time parameters should be set as accurately as possible, based on
the material available. Where the exact time is not known,
investigators should set the time parameters between the earliest
time at which the crime could have been committed and the 
latest time. 
6.8.6 Elimination Criteria 
Investigators need to establish the criteria by which they are
prepared to eliminate members of the TIE category from the crime.
The HOLMES database uses a six point code to do this: 
1 Forensic elimination, eg, DNA, footwear, fingerprint;
2 Description (suspect parameters);
3 Independent witness (alibi);
4 Associate or relative (alibi);
5 Spouse or common law relationship (alibi);
6 Not eliminated.
This is a tried and tested coding system and investigators should use
it whenever they are carrying out TIE enquires. 
Investigators must decide which level of elimination they will apply in
each case. This will depend on the material that is available, the
nature of the offence and the characteristics of the TIE category. 
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For example, forensic material is not always available and there may
be no description of the offender. Although investigators prefer an
independent witness to verify a TIE subject’s alibi, this is not always
possible and it may be necessary to accept an alibi from an associate
or spouse in some cases. 
An important principle of TIE strategies is that implication and
elimination are always provisional and should be rigorously tested
against the material to hand and to any new material that later
becomes available. It is good practice to regard TIE subjects as
being either implicated or eliminated from the TIE category, not 
as being implicated or eliminated as the offender. For example,
someone who has been eliminated against criterion 5, an 
alibi supported by a spouse, can always be re-examined if new
material comes to light which allows a forensic elimination criteria
to be set. 
6.8.7 Conducting TIE Enquiries 
When carrying out TIE enquiries, investigators should be mindful that
the subjects of a TIE category may also be potential witnesses. This
is particularly so where they were present at the scene or where they
are in a group who may know the victim or offender. 
Each subject of the TIE category should be interviewed using the
PEACE model of investigative interviewing to gather information on
the characteristics that are of interest to the investigation. This could
be a description, ownership of vehicles and their whereabouts at
the time of the crime, together with the details of those who can
verify this. 
Where the elimination criteria include forensic material or
fingerprints, these should also be obtained and arrangements made
to have the material tested and the results communicated to the
investigator as soon as possible. 
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PACE Code D (Annex F) 
Fingerprints, footwear impressions and samples given voluntarily
for the purposes of elimination play an important part in many
police investigations. It is, therefore, important to make sure
innocent volunteers are not deterred from participating and their
consent to their fingerprints, footwear impressions and DNA
being used for the purposes of a specific investigation is fully
informed and voluntary. If the police or volunteer seek to have
the fingerprints, footwear impressions or samples retained for
use after the specific investigation ends, it is important the
volunteer’s consent to this is also fully informed and voluntary.
Examples of consent for: 
DNA/fingerprints/footwear impressions
– to be used only for the purposes of a specific investigation;
DNA/fingerprints/footwear impressions
– to be used in the specific investigation and retained by the
police for future use. 
To minimise the risk of confusion, each consent should be
physically separate and the volunteer should be asked to sign
each consent.
Where the elimination criterion is an alibi, investigators must
thoroughly check the alibi with those who can verify it. This process
should enable some subjects of the TIE category to be eliminated
from the investigation. 
Where there is forensic evidence or other compelling material 
linking a TIE subject to the offence or where their alibi is shown 
to be false, it is likely that they will be treated as suspects, see 
6.11 Suspect Strategy. People should not be considered to be 
a suspect merely because their alibi cannot be verified. Further
enquiries should be carried out to gather material that may
implicate or eliminate them from the investigation. 
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Worked example of a TIE strategy
An investigation into the section18 (Offences Against the Person
Act 1861) assault of a man in a busy town centre bar has failed
to identify the suspect and the investigator decides to use a
TIE strategy. 
The suspect parameters are based on witness testimony and are
set as: 
White male, 20 to 30 years, 5’10” to 6’2” tall, short dark hair,
wearing a gold earring in his left ear. 
These details are an amalgam of the descriptions given by
several witnesses. No clothing is included because some
witnesses were unsure of what the offender was wearing. 
The time parameters are between 22:15 hrs and 22:30 hrs.
Again, these are based on the testimony of several witnesses. 
The TIE category is all males in the bar at the time of the offence. 
Populating the TIE category is clearly difficult because it is not
known who was in the bar or even how many people were there. 
The investigator adopts a snowballing technique starting with
the witnesses who are already known. By this method twenty
people are identified and four fit the suspect parameters. Three
of these were with others who provide credible alibis to the
effect that although they were in the bar at the time they were
not involved in the assault. The fourth states that he did not visit
the bar that evening and was alone at home at the time of the
assault. This generates further enquires to test the sighting of
him in the bar at the time of the assault and the use of suspect
management strategies.
6.8.8 Financial Investigation 
Financial investigation may provide intelligence or evidence for use
in all types of investigations, including those with no obvious link to
money or assets. 
It is a cost effective method of investigation and when used with other
tactical options can enhance the efficiency and effectiveness of a
range of investigations. It is not merely a method to recover criminals’
assets following conviction, but is a valuable way of developing
intelligence and adding value to investigations from the start.
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Financial sources of information can support and impact upon many
lines of enquiries in relation to the victim(s), witnesses, scene and
suspect(s). Some of the techniques will also help to identify relevant
lines of enquiry within other strategies.
Everyone in the UK leaves some kind of financial trace. It is this often
unwitting but traceable ‘financial footprint’ (be it by the victim,
suspect, or witness) that the financial investigator will look to exploit.
Ultimately it will support the investigator to:
• Trace or identify suspects, witnesses, victims or missing persons; 
• Prove an association with another person(s);
• Provide information on a suspect and/or victim’s movements;
• Identify the subject’s use of services such as phones, transport
and amenities relevant to the case;
• Identify other offences committed, including tactical options
offered by use of the money laundering offences;
• Identify motives;
• Provide information to address the issue of prolific and priority
offenders where no previous method has been successful;
• Identify the lifestyle of the person, including the assets and
liabilities that they may have.
When considering which types of financial information are
appropriate to the investigation, the reason for the enquiry should
determine the style of the financial investigation required. Any
request for a ‘financial profile’ has to be supported by clear
objectives. If in doubt, it is important to seek advice from the
Financial Investigation Unit.
Investigators should be aware of how financial investigation 
is structured or organised in their force, and how to contact a
financial investigator.
Real-time financial data is, in many circumstances, available to the
investigating officer. The financial investigator is able to make pre-
order enquiries of financial institutions by using the Tournier Rules
(Tournier v National Provincial and Union Bank of England (1924)
1KB 461). These rules permit the financial institution to disclose
information to law enforcement in circumstances that may otherwise
be considered a breach of contract with their customer.
They may disclose financial data in the following circumstances:
• Protect the public;
• Protect their own interests;
• Under compulsion by law:
• With the consent of the owner.
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Ultimately, the financial institution must ensure that it does not
breach customer contracts. This is not a matter directly for law
enforcement agencies as the third-party recipients of this data. 
It is essential, therefore, that the investigating officer is guided by 
the financial investigator on how this financial intelligence is handled
and protected in the early stages of an investigation.
The financial investigator is accredited under the Proceeds of Crime
Act 2002, which gives them access to the UK’s Financial Intelligence
Gateway. They will have up-to-date information for accessing the
majority of the UK financial institutions, and a practical working
knowledge of the diverse protocols for communication with them. 
Other Considerations in Investigative Strategies
In principle, every offender leaving the criminal justice system should
do so without retaining the benefit of their crime. An investigative
objective of identifying and recovering the offender’s criminal assets,
therefore, needs to be set. This should complement traditional
detection and prosecution objectives, and take advantage of the
following opportunities:
• Obtaining sufficient evidence to successfully prosecute the
offender(s) for the offences identified in relation to criminal
property, including the use of the Proceeds of Crime Act offences.
• Identifying and seizing or forfeiting any substantial amounts of
cash believed to have been derived from criminal activity.
• Invoking the provisions of such acts as the Misuse of Drugs Act
1971 (section 27), Powers of Criminal Courts (Sentencing) Act
2000 (section 143) and the Sexual Offences Act 2003 (section
60A), which are designed to enable the use of forfeiture. This is
an effective, additional tool for dealing with criminal proceeds to
its full extent.
• Confiscating any identified criminal assets after conviction.
Confiscation can be triggered following conviction for specified
criminal offences, and occasionally if a defendant absconds before
the conclusion of criminal proceedings. Opportunities to include
cases such as acquisitive crime in the confiscation procedures must,
therefore, be identified early in an investigation. A specialist financial
investigator can then assess assets for potential confiscation or
restraint. This will ensure that assets are protected by restraint orders,
or seizure, using PACE 1984 powers or other available powers, eg, the
Misuse of Drugs Act 1971 (section 23).
Note: The Proceeds of Crime Act 2002 is a powerful investigative
tool. It provides legislation that can support an investigation by
allowing confiscation of the criminal assets of a convicted defendant
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(Part 2); civil cash seizure of amounts of £1,000 or over (Part 5);
money laundering offences (Part 7); and in support of a confiscation
or money laundering investigation by use of production orders,
search and seizure warrants, account monitoring and customer
information orders (Part 8). Under Part 8 of the Act, these orders 
and warrants are not limited to confiscation and money laundering
investigations – depending on the option chosen they may be
available for civil recovery investigations, exploitation proceeds
investigations and detained cash investigations.
The way in which investigators manage communications will have 
6.9 Communications a significant effect on the investigation they are conducting. The
Strategy
main purpose of a communications strategy is to communicate or
receive information which assists investigators to progress their
enquiries. This can be achieved internally by using colleagues and
partners within the criminal justice system and externally by using
the media and other advisers and experts.
Advice from internal and external advisers, particularly in areas
involving the media, community impact, equality, diversity and
human rights issues, should be sought to ensure that an appropriate
level of information exchange is established. This will assist the
investigator to maintain focus on the investigation, while ensuring
that community reassurance and links to community intelligence 
are maintained. Advice can be sought from the following sources:
• Force press office and media advisers; 
• Community equality advisers; 
• Crime reduction advisers; 
• Local community leaders and councillors; 
• Community groups or forums; 
• Lesbian and gay associations; 
• Youth leaders and social services departments;
• Neighbourhood policing teams;
• Partner agencies.
6.9.1 Internal Communications 
An investigator can use a number of methods to communicate
internally. In some cases they may try to develop material to
progress their investigation by informal discussions with colleagues,
or more formally by creating an entry on a daily briefing sheet. 
This may take the form of requesting information or assistance 
to identify likely suspects from descriptions, the MO or the unusual
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clothing worn by a suspect or witness. Other forms of internal briefing
can also be used by investigators to obtain information. 
This includes: 
• Entries on internal bulletin (electronic briefing or paper systems); 
• Daily or extended briefing parades; 
• Force newspaper, intranet systems or video briefings; 
• Posters; 
• Individual briefings to senior officers, community beat officers,
local intelligence, custody officers and staff. 
Formal briefing sessions may be undertaken depending on the
nature and complexity of the investigation and the numbers of
resources being deployed. During the lifetime of an investigation,
briefing sessions should be held daily or weekly depending on the
requirements of the investigation. All briefings should be planned
and structured to provide opportunities for the exchange of
information which will enable the investigator to obtain a clear
update on progress and assist in identifying lines of enquiry. 
Factors to consider are:
• Location – fitness for purpose, briefing or conference rooms; 
• Timing and frequency;
• Notification – attendees such as initial investigators, analysts,
CSIs, intelligence officers, enquiry teams, community beat
officers, supervisors, SPoCs, community equality advisers, crime
reduction advisers; 
• Facilities – video, overhead projectors, flip charts, analysts’ charts,
telephones, PowerPoint presentation facilities, tape recorders;
• Record keeping – maintain records, retain briefing sheets, 
(CPIA considerations);
• Staff required – such as loggist, secretary, shorthand writer; 
• Objective – intended outcome of the briefing or debriefing; 
• Structure – discussion points, main lines of enquiry,
developments, opportunities, threats; 
• Distractions – such as mobile phones and pagers. 
All briefings should follow a similar structure. Regular feedback
should be obtained on the style, content and effectiveness of
briefings to ensure that they are providing the best means of
sharing information and reaching the intended audience. In serious
and complex enquiries a dedicated briefing officer should be used to
ensure consistency. For further information on briefing models, see
Appendix 3 and ACPO (2006) Guidance on the National
Briefing Model. 

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6.9.2 Media Strategy 
Some investigations will attract intense media attention. In
investigations such as domestic murder, violence or sex offences, 
this attention may be local or regional. Some high-profile cases
involving murder, rape, the use of excessive violence, or where the
circumstances are particularly unusual and the victim(s) is a child or
is elderly, this may attract wider national, or even international,
media attention.
There may be a number of reasons why the investigator would wish
to use the media in an investigation. These may include some or all
of the following: 
• Identifying offender(s); 
• Locating a suspect(s); 
• Identifying a victim(s); 
• Appealing for witnesses; 
• To reassure or warn the public. 
Where the nature of an investigation indicates that there are likely to
be high levels of media attention, investigators should, at the earliest
opportunity, inform the force press officer so that they can develop a
media strategy. Early notification is particularly important in cases
which include the ACPO definitions of racially or homophobically
motivated crime. 
In less high-profile cases investigators may manage local media
coverage themselves. Advice and guidance can be obtained from the
force press office in these circumstances. 
Investigators must ensure that a copy of all material released to the
media in the course of an investigation is retained for disclosure
purposes in accordance with the CPIA. See 3.7 Criminal Procedure
and Investigations Act 1996. 

Fast-Track Considerations 
During the early stages of the investigation, a preliminary media
strategy may merely be a case of issuing a holding statement
pending developments within the investigation. The content of
holding statements will vary depending on the circumstances of a
particular investigation, but may include confirmatory information
such as: 
• The police are currently investigating an incident; 
• The general location of the offence; 
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• Initial indications of the nature of the offence (eg, whether a
death is being treated as suspicious); 
• If a death has occurred, the arrangements for a post-mortem
examination to be carried out; 
• Whether an incident room has been set up giving the contact
telephone numbers; 
• An initial appeal for witnesses and/or information;
• Anonymity provisions for victims of sexual offences (the Sexual
Offences (Amendment) Act 1992 entitles victims of most sexual
offences to lifetime anonymity, although this entitlement can
be waived.)
In all circumstances care should be taken to ensure that the content
or timing of a media release is appropriate in the circumstances and
will not cause offence to the victim, their family and friends or the
wider community. The victim and family should be made aware of a
media release prior to it taking place.
Victims should be asked if they agree to their details being released
to the press, although it must be stressed that the press may obtain
them from sources other than the police. 
Identifying the Offender 
In some cases it may be appropriate to make an appeal through the
media to try and identify the offender. This can be by the use of
CCTV footage, photographs, video, E-FITS™ and artist’s impressions.
If E-FITS™ or artist’s impressions are going to be used, care should
be taken about the reliability or credibility of the witness who
provided the description. For further information on the use of
photographs and video footage, see PACE Codes of Practice, Code D,
Part 3 paragraphs 3.28 and 3.29, and ACPO (2009) Facial
Identification Guidance.

In some cases offenders will closely monitor the media for coverage
of an offence. Further information on behavioural analysis can be
obtained from the NPIA Specialist Operations Centre, which can
assist in making direct appeals to suspects. 
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Locating the Suspect 
If a suspect has been positively identified but their location is
unknown, a media appeal can be made to locate them.
Investigators should make every effort to ensure that the
integrity of any future identification procedure is not compromised.
In this situation the investigator is advised to consult the force
press officer, a force solicitor and the CPS. There are a number of
different types of appeal available to investigators. Any appeal
should be authorised by an officer of ACPO rank. Where
identification is not based on photographic evidence, care should
be taken to ensure that descriptions are precise and credible to
avoid a mistaken identification. 
Witness Appeals 
Media appeals can assist the investigation. Appeals should, however,
be carefully considered and coordinated to create the maximum
opportunity for reaching potential witnesses. Investigators should
target appeals at sections of the community most likely to have
witnessed the offence or other significant event. Targeting witnesses
could be based on factors such as their employment, leisure activities
or residence. For the range of media coverage which is available to
assist investigations, see Appeals.
Reassuring or Warning the Public 
Crimes cause concern to the community, and especially to the most
vulnerable members of society. The public become particularly
concerned where a crime is of a violent or sexual nature and the
offender is still at large and may, therefore, strike again. Through
careful use of the media, the investigator must strike a balance
between reassuring the public that every effort is being made to
identify and locate the suspect, while warning the public of the
danger associated with an offender still being at large. They can also
offer sensible, preventive steps that members of the public can take
to avoid becoming such a victim themselves.
Press Conferences 
A holding statement released early in an investigation will lead the
media to expect that further information will be released at a later
date. This expectation can be controlled by giving the media
information about the timing of future press conferences and the
name of the officer who will be conducting them. Provided that
timeframes are reasonable, there is likelihood that the media will be
sympathetic to the victim, their family and the overall aims of the
investigation. Regular press briefings will assist this process. In cases
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where a victim or a member of their family or friends are required to
make an appeal they should be involved in the planning process,
where possible.
The press office can, in consultation with the SIO, assist the
investigation by:
• Handling routine media enquiries; 
• Drafting press releases for approval by the SIO; 
• Dealing with routine press briefings; 
• Organising press conferences and other interviews; 
• Liaising with other agencies involved in the investigation to
coordinate a joint media response (eg, social services, education
or health authorities). 
At the beginning of an investigation, all officers should be briefed
not to talk to the media and clear instructions given that any media
enquiries are directed through the SIO. 
Appeals
The following may be used to target appeals to groups that
investigators believe may have information about an offence.
These include: 
• Newspapers; 
• Television; 
• Radio; 
• Crimestoppers; 
• Posters; 
• Teletext; 
• Trade journals; 
• Internet; 
• Hotlines; 
• Sporting Events. 
Where an appeal is made, adequate facilities should be available to
deal with the response. If a caller feels that they are not being
efficiently dealt with, they may ring off and not call back. As
previously stated, the first opportunity to obtain information may be
the only opportunity. 
In high-profile investigations the force press office can be tasked with
monitoring and retrieving all news coverage of the incident including
appropriate internet sites, eg, news groups or special interest groups. 
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Legal Issues 
Investigators and press officers should be aware of the implications
of the Contempt of Court Act 1981 which, in broad terms, forbids the
use of any material in the media which may prejudice a fair trial. 
Covert policing (sometimes called ‘targeted operations’) can be used
6.10 Covert
in both reactive and proactive investigations. It involves the
Policing Strategy
deployment of tactics, techniques and management processes
designed to ensure that the operation and sources of information it
uses remain covert. 
When investigators are tasked with a covert operation, it is a
fundamental principle that, although they may not determine the
tactics to be employed, they will be responsible for setting objectives,
tasking the covert resources and ensuring that the investigation
remains focused. The success of a covert operation depends on all
those involved in it being aware of the restrictions and requirements
of the tactics and the legislation that regulates them. As with any
investigative action, the purpose of covert policing is to gather
as much material as possible which can be used as evidence in court
or fed back into the force intelligence systems to direct or assist
current and future investigations. 
Where a covert policing strategy is authorised, it is usually coordinated
through a covert operations team which will be self-contained.
A number of covert intelligence techniques are available to progress
an investigation. These include: 
• Static surveillance; 
• Mobile surveillance; 
• Technical options; 
• CHIS tasking; 
• Covert IT applications; 
• Covert financial applications; 
• Undercover options; 
• Covert communications options. 
The type of techniques used during an investigation will be decided
by the intelligence or covert team and are, therefore, outside the
remit of this document. 
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When developing a covert policing strategy, there are a number of
general principles that the investigator needs to consider. These are: 
• Having a good working knowledge of intelligence processes 
and NIM;
• Making themselves fully cognisant of all current, pertinent
intelligence material prior to the instigation of an operation; 
• Anticipating the need for covert policing and making early and
timely bids for such resources (failure to make an early request may
undermine the investigation and valuable material may be lost);
• Ensuring that the covert policing strategy is proportionate to the
overall objectives of the investigation; 
• Knowing how to obtain advice and guidance for covert options; 
• Having a thorough understanding of RIPA and the relevant
aspects of the Police Act 1997;
• Understanding Public Interest Immunity procedures and
legislation, see 3.7 Criminal Procedure and Investigations
Act 1996;

• Ensuring that operations are run on a ‘need-to-know basis’ and
that operational security is maintained at all times; 
• Consulting the CPS at the earliest opportunity (in more complex
cases this may be prior to the commencement of the operation); 
• Establishing a review mechanism if necessary. In serious or
complex investigations which involve a high degree of risk, a
senior officer must authorise and/or review all operations. 
For further information see ACPO (2008) Guidance on the Lawful
and Effective Use of Covert Techniques: The Legal Framework
and Covert Operational Management, 
or contact the SOC on
0845 000 5463.
6.11.1 Arrest 
6.11 Suspect
Strategy

When a suspect has been identified, an investigator must decide
whether the suspect can or should be arrested. The decision to deprive
an individual of their freedom should not be taken lightly. Once a
suspect has been identified, a number of investigative strategies can
be adopted to gather material that will either implicate them in the
offence or eliminate them. Every individual who falls within the
suspect category must be treated in the same way. If there are
specific reasons for not following the same procedure, these should be
recorded in the crime report or in the policy file. 
Investigators should consider the following points before deciding to
arrest an individual. 
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6.11.2 Power of Arrest 
Section 24 of PACE provides the statutory power of arrest for a
person involved in a criminal offence. To make such an arrest an
officer must have reasonable grounds for believing that the arrest is
necessary. When making an arrest, investigators must consider when
and how the arrest should take place. If the offence has already been
committed the officer must have reasonable grounds for suspecting
that the person is guilty of the offence.
6.11.3 Timing an Arrest 
The way in which the identity of the suspect is discovered has a
bearing on how and when an arrest should be made. If there is a
choice, it is usually between making an early arrest and conducting 
a planned arrest. The decision about timing depends on a number of
factors. These factors should be kept under continuous review. If the
circumstances should alter, the decision to make an immediate arrest
or to delay it may have to be amended and the reasons for this
recorded. The factors to consider are:
• Does the suspect pose a serious risk to the safety of the victim,
witnesses or the general public? 
• Is there a likelihood that the suspect will commit further or more
serious offences? 
• Is the suspect likely to destroy, conceal or falsify evidence that
will obstruct the investigation? 
• Is further surveillance or other covert means of surveillance
required? (This will need authorisation under RIPA.)
Background Checks 
When a suspect has been identified, checks should be conducted into
the suspect’s background and lifestyle. These checks can strengthen
and assist the case and should include the following considerations:
• Is the suspect violent? 
• Does the suspect possess any known firearms and/or is there a
history of use of firearms? 
• Does the suspect have or use any other premises? 
• Does the suspect have access to any vehicles? 
• Does the suspect have any previous criminal convictions, arrests? 
• What is their modus operandi (MO)? 
• Are there any known associates? 
• Is there any habitual behaviour associated with the suspect, 
eg, are they a known gambler or are they a known drug addict? 
• Is there any intelligence regarding their previous behaviour 
in interviews? 
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A more extensive list of background checks can be found in MIM. 
In volume crime investigations, research into a suspect’s background
and previous offending behaviour may reveal similarities to the
offence currently under investigation. It may also lead to the
identification of a particular MO which can assist investigators in
identifying other linked offences and to plan for subsequent searches
and/or suspect interviews. 
6.11.4 Searches 
The timing of an arrest provides the investigator with an opportunity
to plan searches of the suspect’s home address (or other premises)
and their vehicles. It may also provide opportunities to recover
incriminating or corroborating material before it is altered, disposed
of or destroyed. A search of a suspect’s premises may also identify
property from other offences or intelligence which can be used to
identify other offenders or associates. Searches of the suspect’s
premises should be carried out in accordance with Code B of the
PACE Codes of Practice. 
When conducting searches or arrests, the investigator should be
aware of Locard’s Principle, see 6.2 Scene Strategy. Evidential
material may have been transferred from the victim or crime scene
onto the clothing of the suspect. The suspect is, therefore, a potential
crime scene which can be harvested, particularly if arrests and
searches take place shortly after the commission of an offence. 
The possibility of cross-contamination must be considered and,
wherever practicable, investigators who have visited the crime scene,
or who have been in close contact with a victim, should not be
deployed to search or arrest the suspect unless they have changed
their clothing. Similar considerations should be applied to the use of
vehicles used to convey victims and suspects. 
6.11.5 Planning an Arrest 
The arrest should be planned where circumstances allow. The
formulation of a plan should take into account resources and
logistics. If several suspects are involved, investigators must decide 
if the arrests need to be coordinated. They must also consider the
method of searching that will be the most appropriate to use 
and whether search warrants will be required. Specific custody
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arrangements may be required in some cases. For example, if several
suspects are going to be arrested simultaneously, it must first be
decided if they should be held at the same or separate police
stations, and whether sufficient facilities are available for this. 
If the suspect does not speak English, an interpreter should be
arranged. Likely defences should be considered and catered for in
interview plans. Preparing an initial interview plan at this stage helps
maximise the detention time available to the investigator, post
arrest. Prior to arrest in serious or complex investigations, specialist
interview advisers should be used or consulted to develop an initial
interview strategy, especially where there are multiple suspects or
unusual features associated with the commission of the offence.
For further information on the use of interview advisers, see
ACPO (2004) Practical Guide to Investigative Interviewing. 
6.11.6 Pre-Arrest Briefings
The arrest and search teams should be briefed both prior to the
arrest phase and the search phase to ensure that all personnel are
aware of: 
• Each officer’s role; 
• The reasons for the arrest. 
The following list is not exhaustive but covers some of the areas
which may have to be considered during a briefing: 
• Circumstances of the offence; 
• Authority for search; 
• Nominated officer in charge of the arrest team; 
• Nominated officer in charge of the search team; 
• Communications; 
• Method of entry; 
• Items to be searched for – clothing, footwear, trophies, weapons; 
• Recording significant statements or silences, see 6.11.7 Post Arrest;
• Methods of recovery and cross-contamination; 
• Exhibits officer; 
• Loggist;
• Health and safety; 
• Transport of suspects – the location of the custody office; 
• Interview teams; 
• Debrief – time and location.
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6.11.7 Post Arrest 
Once in custody, the suspect’s detention is controlled by PACE, section
30 and PACE Code C which provide detailed guidance on the
treatment of people in police detention. At the time of arrest and
before the suspect is delivered to the police station, anything that the
suspect says must be fully recorded. In particular any significant
statements, eg, ‘I don’t know what you’re talking about’, made by
the suspect post arrest and before formal interview should be
recorded. Arrest teams should be specifically briefed not to question
or interview suspects further unless there are imminent threats to life
or property. All questioning of a suspect must be conducted in
accordance with PACE. The investigator will have an opportunity to
challenge any significant statements in formal interview, after
presenting contradictory evidence to the suspect. At the conclusion of
the arrest and search phases, the teams should be debriefed by a
nominated officer to ensure that all relevant material has been
identified and documented.
6.11.8 The Identification of a Suspect 
In some cases the suspect will be identified beyond reasonable
doubt from the outset of an investigation. They may have been
caught red-handed or arrested during the initial investigative
response. Alternatively, suspects may be identified from material
gathered during the investigation, eg, fingerprints or DNA samples
left at the scene. Whenever a suspect’s identity becomes known to
the investigation, consideration must be given to formal
identification procedures. PACE Code of Practice Code D provides
guidance to investigators on identification procedures. MIM also
gives advice and guidance on appropriate identification procedures
to adopt for the identification of a suspect whether they are known
or unknown.
The first principle of identification evidence is that failure to
accurately record the description of a suspect as soon as it becomes
available, and failure to use that description as part of the
identification process, can seriously undermine the chances of a
subsequent conviction. As a rule, investigators should bear in mind
that recognition does not amount to identification and that where a
witness claims to recognise a suspect, identification procedures must
still be followed. 
Deciding on which identification procedure to adopt during an
investigation should be made in consultation with the identification
officer. Due consideration must be given to the procedure most
suited to the witness.
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Where investigators are conducting interviews with witnesses and
identification is likely to be an issue, guidelines contained in
R v Turnbull (1977) and captured in the eight-point mnemonic
ADVOKATE will assist them to secure the best evidence: 
– Amount or length of time the witness had the suspect
under observation; 
– Distance between the witness and the suspect during 
the observation;
– Visibility conditions during the observation; 
– Obstructions to the observations, whether they temporarily
or partially inhibited the observation; 
– Whether the suspect is known to the witness in any way; 
– Any particular reason the witness has for remembering the
suspect or event; 
– Time the witness had the suspect under observation and
the amount of time elapsed since the event; 
– Errors in the description provided by the witness compared
with the actual appearance. 
Descriptions should be obtained as soon as possible while the
recollection is fresh in the mind of the witness. In some cases the
suspect may still be in the locality and may not yet have had the
opportunity to alter their appearance or to conceal or dispose of
incriminating evidence.
Where the suspect is not known, the following identification
procedures should be used:
• Street identification – when a witness can be taken to the
particular location to see whether an identification of a suspect
can be made; 
• Showing photographs to a witness; 
• Showing video footage or photographs of an incident to a witness;
• Using facial imaging techniques, which may include artist’s
impressions, composites and E-FITS™ (electronic facial imaging
technique). For further information on E-FITS™, see ACPO
(2009) Facial Identification Guidance.

Identification Procedures Where the Suspect Is Known
‘Known’ in this sense means that the police have sufficient
information to justify the arrest of a particular person as a suspect
for an offence. The initial identification may be the result of one of
the procedures outlined earlier in this section. Where the suspect
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is known and the witness is available to take part in an identification
parade, the identification procedures should be used in the
following sequence:
• Video Identification Parade Electronic Recording (VIPER) or
other approved video identification techniques;
• Formal identification parade
• Group identification;
• A videofilm;
• A confrontation.
A video identification shall be the first procedure offered unless 
an identification parade is more practicable and suitable. If a 
group identification is more practicable and suitable than both a
video identification and an identification parade, then this must be
offered first.
The use of VIPER or video identification procedures does not require
the suspect to attend, thereby reducing the time required to arrange
formal identification procedures and giving witnesses an early
opportunity to view the parade. Witnesses may also feel less
intimidated when picking out an image from a computer screen than
by attending a formal identification parade at a police station.
However, video identification procedures preclude the witness from
seeing the suspect walk or move or use a particular phrase or words,
see 6.11.9 Voice Identification.
Failure to ensure that the procedures set out in PACE Code D are
followed can seriously undermine the strength of the prosecution
case or give the defendant grounds for appeal against a conviction.
However, there may be circumstances where, following the judgment
in the case of R v Long [1991], the court will accept identification
evidence that has not been gathered in accordance with PACE Code
D. For example, where the witness recognises the suspect when they
meet accidentally in the street.
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6.11.9 Voice Identification
In some cases voice identification can be used to support other
identification evidence, eg, where the suspect’s facial features are
obscured but they speak clearly to the victim or witness. There are
two categories of voice identification: 
• Identification – where the witness identifies the voice of
someone they know; 
• Recognition – where the witness does not know the voice of the
suspect but would be able to pick out the voice as being distinct
from other voices. 
Voice identification investigators should refer to MIM.
6.11.10 Suspect Interviews 
Suspect interviews must be carefully planned. The interviewer should
possess a comprehensive knowledge of all the material gathered
during the investigation and plan how this should be introduced in
the interview. Consideration should also be given to the competency
and capability of the staff who conduct the interview. In volume
crime cases inexperienced investigators can request assistance in
planning and conducting interviews from experienced colleagues
and supervisors. This may include the ‘downstream’ monitoring
of the interview.
In serious cases additional support can be provided by officers with
advanced interviewing skills. Specialist interview advisers or
behavioural analysts can also assist with the preparation of interview
plans. Information regarding interview advisers and behavioural
analysts can be obtained from the NPIA Specialist Operations Centre.
Interviews with suspects should be conducted using the PEACE
model of interviewing. 
The suspect’s previous bad character can now be introduced during
the interview process. For further information see ACPO (2008)
Practice Advice on Evidence of Bad Character, 
Second Edition. 
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Evidence of Bad Character 
The CJA makes fundamental changes to the admissibility of
evidence relating to character in respect of defendants and
others. In particular, the Act provides for the admissibility of
previous convictions in support of the propensity to commit like
offences and/or to be untruthful. Common law rules, in the main,
are abolished. 
Bad character evidence is evidence of, or a disposition towards,
misconduct rather than evidence relating to the facts in issue.
Misconduct includes the commission of an offence or other
‘reprehensible behaviour’.
Bad Character of Persons other than the Defendant 
Such evidence is only admissible if the evidence is important
explanatory evidence or has substantial probative value in
relation to a matter in issue, and is of substantial importance to
the case as a whole. It can also be admitted if all parties agree
to its admissibility.
Defendant’s Bad Character 
Evidence of the defendant’s bad character is admissible where: 
• All parties agree to its admissibility; 
• The evidence is adduced by the defendant, or is given in
answer to a question asked by him or her in cross-
examination and intended to elicit it; 
• It is evidence with important explanatory value; 
• It is evidence going to a matter in issue between the
defendant and prosecution; this will include evidence to
show that the defendant has a propensity to commit
offences of the kind with which he or she is currently charged
as well as evidence to show a propensity to be untruthful; 
• It has substantive probative value in relation to an important
matter in issue between the defendant and a co-defendant; 
• It is evidence to correct a false impression given by 
the defendant;
• The defendant has made an attack on another person’s
character.
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Dealing with Bad Character at Interview 
Prior to the CJA, the interviewer could refer to previous bad
character. The interview was not restricted to issues of material
and admissible evidence. Such references stood to be removed,
and there was a risk that subsequent admissions might be
disallowed if they were seen to follow from oppressive
questioning. The present law, by making a propensity to be
untruthful and/or a propensity to commit offences relevant as
evidence, reduces this possibility. As a result, officers should
address these issues in interview. 
Evidence of bad character is only admissible if the appropriate
conditions apply. The investigator should, therefore, identify
those conditions in framing questions. If a propensity to similar
offending is the issue then the similarities should be referred to.
If dishonesty is relevant, the defendant will have had to have
made a denial which is disputed by him or herself through
another party; previous examples of false denials can then
be raised.
Interview plans should be prepared using information from the
available material. MoJ (2011) Achieving Best Evidence in
Criminal Proceedings 
and ACPO (2004) Practical Guide to
Interviewing 
provide detailed guidance on interviewing 
suspects and pre-interview planning. During the interview, the
investigator should consider the seven principles set out in the 
ACPO (2009) Briefing Paper on National Investigative
Interviewing Strategy, 
see 6.5.6 Witness Interviewing.
6.11.11 Pre-Interview Briefing (Disclosure) 
An investigator needs to develop a clear strategy for pre-interview
briefing. This briefing should strike a balance between providing
sufficient information to enable a legal representative to properly
advise their client, and giving too much information that produces 
an adverse impact on the subsequent interview. The investigator is
under no legal obligation to disclose anything at this point. It may,
however, be beneficial to make a limited disclosure or to adopt a
staged disclosure strategy.
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Good practice has identified that where pre-interview disclosure
is made, it is supplied on tape or in written format and the
disclosure is acknowledged by the suspect or their representative.
At the start of an interview any material that has been disclosed
should be summarised and again acknowledged by the suspect or
their representative.
In suspect interviews the role of the defence solicitor is to advise
suspects of their rights and to protect their client’s interests.
Investigators should strive to build a rapport with the suspect 
and with their solicitor, and avoid confrontations with them.
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Management
This section sets out a number of management issues
which apply to the various phases of an investigation.
The extent to which investigators need to manage
them will depend on the type and complexity of
the investigation.

The majority of volume crime investigations are
managed and conducted by the first attending officer
with some general supervision or review of the
investigation by an evaluator or supervisor. In serious
or complex cases the initial management of the
investigation remains the responsibility of the first
attending officer, but will later be taken over by an
IO or SIO. 

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Contents
7.1
Managing an Investigation
165
7.2
Managing Resources
165
7.3
Managing People
167
7.4
Managing Risk
169
7.4.1 Community Impact Assessment
171
7.5
Quality Assurance
172
7.6
Managing Actions
172
7.7
Record Keeping
173
7.7.1 Exhibit Management
174
7.7.2 Handover
175
7.7.3 Briefing and Debriefing
175
7.8
Summary
176
Figures
Figure 7 Managing Resources
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The CPIA Code of Practice under Part II states that: 
7.1 Managing an
Investigation

All investigators have a responsibility for carrying out the
duties imposed on them under this code, including in
particular recording information, and retaining records
of information and other material.
The investigator is responsible for managing these processes. 
The successful management of an investigation requires planning,
organisation, control and motivation. An investigation may entail
managing any or all of the following: 
• Resources; 
• People; 
• Risk; 
• Quality assurance; 
• Actions; 
• Record keeping; 
• Auditable decision making; 
• Communications.
The key to effective resource management is planning and foresight.
7.2 Managing
Investigators must, at the earliest opportunity, identify the resource
Resources
needs of an investigation. 
These will vary depending on the crime type and whether it is a
volume crime or a major investigation. Figure 7 illustrates the
different types of resources available to investigators. When deciding
on the resources required, the investigator must consider the
appropriate level of investigative response, the availability and cost
of the required resources and whether their use is proportionate. 
Some resourcing decisions in volume crime investigations will be
outside the investigator’s control, and the use of specialist or
technological resources will primarily be driven by local force
policies and budgets. The Tactical Tasking and Co-ordinating
Process will often dictate the level of response and resourcing which
will be allocated to volume crime investigations in line with local
policing priorities. 
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Figure 7 – Managing Resources
Financial Resources
Intelligence Resources
• Central funding
• Local intelligence systems
• Local funding
• National intelligence
• Budget holders
systems
• Forensic
• Crime management
Human Resources
• Victim/witness management 
systems
• Staff overtime 
• CHIS
• Police staff
• Travel
• Surveillance (physical and
• Interpreters
• Rewards
technical, overt or covert) 
• Community leaders
• Expenditure authorisation
• Members of the public
• Victims and witness
• Suspects
• Experts
– FSS services
Investigator as Resource Manager
– Home Office experts
– SOC experts
– SOCO services
– Hi-Tech analysis
Communication Resources
Physical Resources
– Support groups
• Witness liaison
• Telephone
• Offices
• Community support
• Force radios
• Office materials
groups
• Commercial media
• Vehicles
• Printing
• Detention facilities
• Email
• Interview facilities
• Internet access
• Storage facilities
• Crimestoppers
• HOLMES
• Technology
• Exhibit store
Where resources are limited, investigators must prioritise the needs
of the investigation in line with the resources available. This can be
particularly difficult during the initial investigative phase, see
4.4.2 Initial Investigation. 
For major investigations, significant guidance is available to
investigators such as MIM and MIRSAP. In those forces without
specialist units to deal with major investigations, SIOs or IOs may
have to negotiate sufficient resourcing through supervision or local
command for the specific needs of the investigation. 
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Under the CPIA there is now a greater emphasis on full and accurate
record keeping within an investigation, see 3.7 Criminal Procedure
and Investigations Act 1996. 
This includes the use of resources.
Where it is anticipated that significant resources will be used in an
investigation, investigators should record in the crime report, policy
file or decision log the following information: 
• The purpose for which resources were requested (including the
reasons for the request and the estimated time the resources
would be required for);
• The type of resources allocated;
• The reason for requesting the resources;
• What was actually achieved by using them?
If an investigation or its methods are reviewed by a supervisor,
independent review panel or court, those undertaking the review
must be able to determine that the investigator’s decisions and
actions were reasonable. Accurate record keeping will provide a key
point of reference in the event of any enquiry or review. 
Where resources have been allocated for a particular aspect of an
investigation (eg, house-to-house enquiries) the investigating officer
must ensure that resources are deployed and managed efficiently
and that accurate records are kept of where and how they are used. 
Managing people is integral to any investigation. Smith, N. and
7.3 Managing
Flanagan, C. (2000) The Effective Detective: Identifying the
People
skills of an effective SIO noted there are two components to
people management within an investigation. Managing colleagues
within the Police Service, and managing relationships with
individuals who may assist the investigation or may provide material
to the investigation. 
Depending on the nature and complexity of the investigation, an
investigator will have to manage and interact with a variety of
diverse individuals. These may include not only victims, witnesses
and suspects, but also: 
• Colleagues; 
• Various experts or subject specialists; 
• CHIS; 
• Solicitors or legal representatives (defence and prosecution); 
• Representatives of partner agencies (eg, Social Services, the
Probation Service, UK Border Agency).
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Given the wide range of individuals that investigators may have to
interact with, the following list provides some behavioural traits to
assist them in managing colleagues and others. (This is not a
definitive list, nor is it in any particular order of priority.)
• Communication
Investigators must be able to communicate effectively with 
a wide range of people and adapt quickly to change.
Through effective listening, interpretation and understanding
of information, they can formulate questions and test their
understanding of the case. The ability to transmit and 
receive information accurately is crucial to the progress of 
an investigation.
• Sensitivity and Perception 
Investigators need to be conscious of their own behaviour
and its possible effect on others. Avoiding stereotyping,
personal bias and discrimination, and being aware of other
people’s reactions, will assist investigators in building and
maintaining productive relationships.
• Practical Support 
Investigators should identify the individual needs of victims
and witnesses and, as far as is practicable, offer support and
assistance in meeting those needs. 
• Influencing Skills 
This is the ability to develop logical and practical arguments
or proposals that are likely to identify solutions to problems
and be able to persuade people to take a different stance 
or viewpoint.
• Assertiveness 
This is the ability to express beliefs and opinions in a
forthright manner while taking account of other people’s
rights and opinions. The investigator’s reactions to others
should be positive and not aggressive. 
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By law (eg, Human Rights and Health and Safety Legislation) the 
7.4 Managing Risk
police are required to identify, assess and manage risks to prevent 
or reduce the likelihood or impact of harm to:
• Victims;
• Witnesses;
• Suspects;
• The general public;
• Police employees and the Police Service;
• The emergency services;
• The local community;
• Local businesses.
The police are constantly making decisions about situations where
any particular outcome cannot be guaranteed. All areas of policing
are, therefore, susceptible to the risk of harm. Investigation is no
exception. Particular risk areas involve:
• Parameters of the investigation (eg, failing to consider the wider
implications and taking too narrow a focus, failing to assign
sufficient time or resources);
• Evidence collection and presentation (eg, accepting information
at face value, allowing evidence to be corrupted, weaknesses in
taking statements or verifying particulars);
• Individuals or groups of individuals (eg, exposing them to harm
by not providing them with timely advice or information, failing
to ensure they attend court on time).
Forces are responsible for implementing the systems, structures and
processes needed to achieve a balance between the harms and
benefits that can result from their actions. These should be robust,
proportionate, carefully considered and as non-bureaucratic as
possible. They will include providing appropriate levels of support,
advice, information and training. Investigators should be familiar
with their local risk assessment and risk management processes.
Every investigator is responsible for recognising and managing potential
risks by undertaking appropriate risk assessments. Steps include:
• Recognising a person or situation as posing a risk;
• Assessing something as a risk in terms of probability or
seriousness of likely harm;
• Identifying suitable responses (ie, correctly weighing up what
steps might be taken to deal with the risk);
• Selecting the most appropriate response;
• Monitoring what happened as a result of any decision made or
action taken.
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The interventions or measures chosen to deal with risk can range
from being relatively simple, such as provision of crime prevention
advice, to the complex, eg, providing witness protection.
The selected response should be:
Proportionate
Lawful
Necessary
Ethical.
To manage risk investigators must be able to:
• Identify harm that may occur during an investigation and its
likely impact upon individuals, the investigation or the
organisation itself;
• Make appropriate decisions to manage identified risks;
• Keep records demonstrating the steps taken to manage and
monitor risk;
• Communicate details to others (eg, colleagues, victims or
witnesses) of identified risks or the strategies established to 
deal with them.
The inclusion of the assessment of risk as an integral part of the
investigative process increases the likelihood of making better
professional judgements in uncertain conditions. Other benefits
include fewer unwelcome surprises and higher victim satisfaction.
By taking a risk assessment approach, an investigator’s decision will
be more easily justified. ACPO (2007) Guidance on Protecting the
Public: Managing Sexual Offenders and Violent Offenders
states that if the following elements have been adhered to, they are
likely to make a decision ‘defensible’:
• All available information has been collected, recorded and
thoroughly evaluated;
• Policies and procedures have been followed;
• Reliable assessment methods have been used where available;
• All reasonable steps have been taken and any information 
acted upon;
• Practitioners and their managers have communicated with each
other and with other agencies, been effective and proactive, and
have adopted an investigative approach;
• Decisions have been recorded (and subsequently carried out).
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During the course of an investigation, risk assessment should be
subject to regular reviews to ensure that identified risks have been
adequately managed. If any new risks are identified or the nature of
the investigation changes significantly, a new risk assessment should
be carried out.
Further guidance on the assessment and management of risk is
available from the Health and Safety Executive (HSE) at
http://www.hse.gov.uk/
7.4.1 Community Impact Assessment
One of the risks that investigators may have to manage during the
course of an investigation is the impact that crime will have on the
local community (in particular the impact on vulnerable or minority
groups). Community impact assessments will not, however, need to
be routinely undertaken. For various reasons, some investigations
attract increased attention in the local community or the media.
This may be because of the seriousness of the offence or because
there is a particular feature which raises public concerns (eg, racist
elements, or a series of similar crimes in a small geographical area).
Investigators will need to assess the effect a particular crime has
had on the community and each assessment should be decided on
a case-by-case basis.
Through consultation and the use of intelligence, the assessment will
help to improve community confidence and encourage the free flow
of information to assist in monitoring community reactions. Where
consultation has taken place with the local community and
interested parties, thought should be given to how information can
be shared, acted on and, if appropriate, disclosed. Any community
impact document will be subject to the provisions of the CPIA.
For further information on community impact assessments and when
they may be appropriate, see MIM.
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Forces have their own quality control and investigative supervision
7.5 Quality
systems to ensure that minimum standards of investigation are
Assurance
complied with. In addition, ACPO (2009) Practice Advice on the
Management of Priority and Volume Crime, 
Second Edition
advocates methods and processes for managing volume crime.
Investigations of more serious crime, such as homicide, will be
subject to a formal review procedure at force level.
The statutory charging scheme also provides quality assurance of the
investigation process. Following a review of form MG3, the CPS has
the discretion to direct the investigator to undertake further
investigative actions as required to ensure that the case against the
offender is evidentially robust. 
Irrespective of this additional review of an investigator’s work,
there still remains a primary obligation on supervisors and
managers to ensure that initial investigative actions are conducted
thoroughly and in a timely manner. This quality assurance process
will provide information to supervisors and managers that will
assist in developing investigators’ skills through their personal
development reviews. 
The nature and complexity of an investigation will, to some extent,
7.6 Managing
dictate the investigative action that investigators must manage.
Actions
Force policies may also dictate the level of investigative response
and activity.
Most volume crime investigations are conducted by a sole
investigator, assisted in varying degrees by crime scene examiners or
other specialists. In these cases the investigator has to prioritise their
investigative actions, some of which will be evident from the initial
attendance to the victim or the crime scene.
Other investigative action entails developing and completing lines
of enquiry, and recording the decision-making process which
underpins this action in the crime report or associated documents.
This assists colleagues, supervisors and managers to verify the
progress of the investigation and to advise on prioritisation issues
to support the investigation.
In major or serious criminal investigations more than one
investigator may need to be deployed. These investigations are also
likely to generate multiple investigative actions and the collation of
numerous documents. ACPO (2005) Major Incident Room
Standardised Administrative Procedures (MIRSAP) 
advises on
the procedures to adopt for the effective deployment and
management of investigative resources and documentation.
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An auditable record of the reasons for taking a particular
7.7 Record Keeping
investigative action must be kept. This will provide invaluable
information for the initial and any subsequent investigator, and for
the organisation. It will also provide an overview of the investigation
and can be used to record areas such as:
• Investigative actions (the options preferred and considered); 
• Any investigations strategy used; 
• Risk assessments; 
• Resource considerations; 
• Health and safety considerations. 
Records are kept in a variety of formats depending on the
seriousness and complexity of the crime under investigation.
Common formats include:
• Crime reports for most types of volume crime investigations; 
• Decision logs or policy files for serious or complex investigations.
The type of format used will be subject to local force policies 
and procedures.
Timely and accurate records provide an audit trail of why decisions
were taken and what factors were considered or discounted by the
investigator in arriving at that decision. The recording of this
information demonstrates the accountability and integrity of the
investigative process. 
Auditable decision making means: 
• Recording what has been done and why it was done; the 
reasons for taking particular investigative actions and what the
outcome was;
• Providing an audit trail that can be followed in the event of
review, scrutiny, or new material coming to light. 
Investigators must be able to justify why a decision was made and
be confident that others will be able to understand why they arrived
at that decision. Auditable decision making enables investigators to
recall a particular investigation long after the event. An individual’s
recollection of events may become inadvertently distorted, even over
a short period of time. Access to a record of decisions made at the
time of the investigation is more likely to provide accurate and
credible information. 
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If new information subsequently comes to light, the original
investigative actions can be reviewed, documents and exhibits
can be located, and the investigation progressed without any
unnecessary delay.
Keeping full and accurate records may also reduce the risk of cases
collapsing where doubt can be cast on the integrity of evidence or
there are technical faults in the evidence-gathering process. It also
avoids unsafe convictions and the costs involved and any attendant
negative publicity associated with appeals and re-trials.
Note: Where investigations involve the Official Secrets Act and
Counter Terrorism, investigators should be aware that restrictions will
apply in terms of what can be recorded or referred to.
For further information on decision making and policy files see: 
ACPO (2006) Murder Investigation Manual; 
ACPO (2008) Practice Advice on Analysis.

7.7.1 Exhibit Management
During the course of an investigation, the investigator will gather
material which may be in a physical, documentary, or biological
format. This material will be referred to as ‘exhibits’ and will require
collation, examination and storage to maintain its integrity and
provenance. The investigator must maintain accurate and
comprehensive records of all exhibits. As each exhibit is recovered
during an investigation, a record should be compiled detailing the: 
• Precise description of the material recovered; 
• Precise location of recovery; 
• Time, day and date of recovery; 
• Individual who produced it; 
• Individual who recovered it; 
• Location and method of storage. 
If the material is subsequently removed from storage, this should
also be recorded, detailing the reasons for this and the name of the
person who removed it. Advice on the recovery, handling and storage
of exhibits can be obtained from CSIs or CSMs and supervisors. 
In large-scale, serious or complex enquiries a dedicated exhibits
officer may be appointed. The exhibits officer is responsible for
maintaining an exhibit register detailing all of the above.
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Additionally, they will be responsible for bringing significant items 
to the attention of the investigator at the earliest opportunity. 
See MIRSAP for further information on the management of
property and exhibits.
Indexing 
In large and complex enquiries, records of relevant information are
maintained on indexes. MIRSAP gives guidelines for indexing
material gathered during the course of an investigation. These
guidelines can be followed using the HOLMES 2 database or on what
are commonly known as ‘proper indexing systems’, ie, card indexes
to manage actions and material. Investigators should familiarise
themselves with those systems available to them. 
7.7.2 Handover
This refers to the manner in which the responsibility for an
investigation passes from one investigator to another. The initial
investigator must record the full extent of their actions. The point of
handover should be explicit and documented, and investigators must
ensure that all available information about the conduct of an
investigation has been fully communicated to any new investigator.
This will ensure that all investigative opportunities are progressed. 
The principle of ‘passing the baton’, therefore, applies. In the
majority of volume crime cases the handover can be recorded on 
the crime report or associated document. In serious cases a verbal
briefing/debriefing may be necessary, to fully update the new
investigator and to allow for the dissemination of information or the
physical transfer of documents or exhibits. In certain cases it will also
allow the initial investigator to communicate to the new investigator
any actions that need to be conducted or finalised. A full record
should be made of the handover process. 
7.7.3 Briefing and Debriefing 
Briefing is a method of imparting or exchanging information.
Briefings can be to senior investigators and managers or to
colleagues and team members. They can also be used as a means
of motivating people to work as a team by explaining what is
expected of them, and to measure and monitor the progress towards
an objective.
Debriefing is an opportunity for the investigator to obtain and share
feedback on the outcomes of an investigation. Briefing and
debriefing are powerful learning tools for the investigator and the
organisation, identifying good practice and areas for development.
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Effective briefing and debriefing require knowledge of the:
• Subject – outline of the facts or circumstances to the audience; 
• Individuals to be briefed – what is their level of competence 
and capability;
• Objective – the investigator must ensure that they and the
audience know what they want to achieve, how this will be
accomplished and by whom. 
All of the above require the investigator to undertake a degree of
planning. Briefings should not be conducted informally. All briefing
and debriefing notes should be kept for disclosure purposes. 
For further information on briefing and debriefing, see ACPO (2006)
Guidance on the National Briefing Model 
and MIM. See also
Appendix 3 for the IIMARC and SAFCOM briefing models. 
Investigators must be able to manage themselves and their time
7.8 Summary
effectively in order to be able to successfully manage all aspects of
an investigation. 
To manage yourself effectively you have to be aware of the
policies which affect your work. You have to establish what
guidelines exist to help you deal with eventualities. Again
do not wait to be told – you find them out for yourself.
Armstrong (1990) 
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Glossary
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5x5x5
An Information/Intelligence Report where the source, the intelligence
and the way in which the material should be disseminated (known as
the handling code) have all been evaluated and assigned a grading
between 1 and 5.
ABE 
Achieving Best Evidence
ACPO/ACPOS 
Association of Chief Police Officers – police bodies which provide 
a professional corporate view on policing in England, Wales and
Northern Ireland (ACPO) and Scotland (ACPOS). 
AG
Attorney General
Analysis
Analysis is the process of collecting, reviewing and interpreting a
range of data and making inferences and recommendations from it.
Analysis identifies patterns in information and draws inferences
based on what is occurring to allow operational, strategic and tactical
decision makers to decide on appropriate further activity to prevent,
reduce and detect crime and disorder. 
ANPR 
Automatic Number Plate Recognition is the automatic image
capture and recognition of vehicle registration numberplates and 
the checking of those details against a number of databases.
BADMAN
Behavioural Analysis Data Management Auto Indexing Network. 
This is a database developed by Surrey Police giving details of over
900 national (and some international) rape offences, coding
offender behavioural patterns and crime characteristics. Developed
as an offender profiling database, it represents a sample of all sexual
offences dating back to 1973.
Superseded by ViCLAS due to greater sample size.
BCU 
Basic Command Unit – a geographical area within a police force
(eg, Metropolitan Police) also known as Area, Division or Operational
Command Unit.
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BIA 
Behavioural Investigative Adviser. The role of the BIA involves
providing advice and consultation on behavioural matters in
serious crime, on requests for assistance from police forces and
other agencies. 
BVPI 
Best Value Performance Indicator
Call taker 
This refers to the person from the Police Service who acts as the
initial point of contact for victims or witnesses reporting a crime has
occurred or is in progress. The call taker’s actions will form the
beginning of the investigative process as they decide the initial
course of action to take.
Catchem 
Centralised Analytical Team Collating Homicide Expertise
Management. Database developed by Derbyshire Constabulary
representing a distillation of facts from a comprehensive study of
sexually motivated murders of children and the persons who have
committed them over the past 43 years. 
Category A+, A, B, C
The categorisation of investigations acts as a guide to the initial
deployment of resources. The initial categorisation is subject to a
periodic review as the investigation proceeds. 
Category A+
A homicide or other major investigation where public concern and
the associated response to media intervention is such that normal
staffing levels are not adequate to keep pace with the investigation.
Category A
A homicide or other major investigation which is of grave public
concern or where vulnerable members of the public are at risk, where
the identity of the offender(s) is not apparent, or the investigation
and the securing of evidence requires significant resource allocation.
Category B
A homicide or other major investigation where the identity of the
offender(s) is not apparent, the continued risk to the public is low
and the investigation or securing of evidence can be achieved within
normal force resourcing arrangements.
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Category C
A homicide or other major investigation where the identity of the
offender(s) is apparent from the outset and the investigation or
securing of evidence can be achieved easily.
Caution 
A police caution is a formal warning usually delivered by a senior
officer in uniform at a police station. It is an alternative to
prosecution, normally for first or second-time offenders committing
less serious offences. A caution should be recorded by the police and
is citable in court as part of the offender’s antecedent criminal history. 
CC
Crown Court
CCA 
Comparative Case Analysis is a method for identifying series or linked
events. CCA aims to find patterns within the detail of an incident or
crime event that will potentially link them because they are distinct
enough from other events. 
CCTV
Closed-Circuit Television
CDA
Crime and Disorder Act 1998
Charging
Prosecution by way of a summons
CHIS
Covert Human Intelligence Source. This is someone who establishes
or maintains a personal or other relationship with another person for
the covert purpose of using that relationship to obtain information,
to provide access to any information or to disclose information
obtained as a consequence of that relationship. 
CHRIS
Crime Handling and Reporting Information System
CICA
Criminal Injuries Compensation Authority
CID
Criminal Investigation Department
CISO
Crime Investigator Support Officers 
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CJA 
Criminal Justice Act 2003
CJS
Criminal Justice System
COS
Crime Operational Support
CPA
Crime pattern analysis identifies the nature and scale of emerging
and current crime and disorder trends, linked crimes or incidents, 
hot spots of activity and common characteristics of offenders and
offending behaviour. There are four main types of CPA:
• Hot spot identification;
• Crime and incident trend identification;
• Crime and incident series identification;
• General profile analysis.
CPD
Continuing Professional Development
CPIA 
Criminal Procedure and Investigations Act 1996
CPS 
Crown Prosecution Service
Crime hot spots 
Hot spots are geographical areas with significantly higher rates of
recorded crime and/or incidents than surrounding areas. They can be
short term, such as an area with a low burglary rate experiencing a
sudden increase, or long term, for example, a problem residential
estate. (See CPA.)
CRA
Crime Reduction Adviser
CSI
Crime Scene Investigator
CSM
Crime Scene Manager
CSP
Communication Service Providers
DBIS
Department for Business Innovation and Skills
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DfT
Department for Transport
DNA
Deoxyribonucleic Acid
Doctrine
Doctrine is the term sometimes used to refer to documents produced
by the NPIA’s Practice Improvement Unit. The principal purpose of
doctrine is to provide a framework of guidance for policing activities
and underpin police training and operational planning. The
development of doctrine follows a hierarchy that reflects different
levels of status for the Police Service. 
DPP
Director of Public Prosecutions
DVLA
Driver and Vehicle Licensing Agency
EA (2010) Equality Act 2010
EA 2010
Equality Act 2010
ECHR
European Convention on Human Rights
E-FIT™
Electronic Facial Identification Technique
EHRR
European Human Rights Reports
Email
Electronic Mail
ESDA
Electro Static Detection Apparatus (Electro Static Document Analyser)
Exhibits Officer
This person is responsible for liaising with the crime scene
investigators and forensic science providers to ensure that the
recovery, handling, storage and submission of all relevant exhibits are
undertaken. The exhibits officer works closely with the investigating
officer and deals with information concerning submissions and the
results of forensic examinations.
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Fast-Track Action 
Any investigative actions which, if pursued immediately, are likely to
establish important facts, preserve evidence or lead to the early
resolution of the investigation.
FIB 
Force Intelligence Bureau
FLINTS
Forensic-Led Intelligence System
FLO
Family Liaison Officer
FME
Forensic Medical Examiner
FSS
Forensic Science Service supplies forensic science services to police
forces in England and Wales, as well as being a source of training,
consultancy and scientific support.
Golden Hour principle
The Golden Hour refers to the period immediately following the
commission of an offence when material is abundant and readily
available to the police.
H2H/HtoH
House-to-House enquiries enable investigators to identify witnesses;
to identify suspects; and to gather local information and intelligence.
They can also be used to provide public reassurance.
HMIC
Her Majesty’s Inspectorate of Constabulary
HMSO
Her Majesty’s Stationery Office
HO
Home Office
HOLMES
Home Office Large Major Enquiry System
Force database – computer system for Major Incidents
HORT1
Home Office Road Traffic form
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HRA
Human Rights Act 1998
HSE 
Health and Safety Executive
ICIDP
Initial Crime Investigators Development Programme
IDENT1 
IDENT1 has superseded the National Automated Fingerprint
Identification Service (NAFIS).
Incident Analysis
Incident Analysis involves examining the detail of an incident or
series of incidents.
Incident analysis can involve looking at a number of areas:
• Events (the entire timespan of an incident or specific timeframes
within this);
• Themes (movements of suspects, observations of witness, 
routes travelled);
• Identification of new lines of enquiry (new potential witnesses);
• Gaps and conflicts in information (5WH matrix).
Information
Information refers to all forms of information obtained, recorded
or processed by the police, including personal information 
and intelligence.
INI
Impact Nominal Index enables an officer in one force to quickly
establish whether any other force holds information on a person of
interest in any of their main operational systems – crime, custody,
intelligence, domestic violence, firearms and child protection. 
It comprises a database of nominal information downloaded from
local police systems via the Criminal Records Bureau.
Intelligence
Intelligence is defined as information that has been subject to a
defined evaluation and risk assessment process in order to assist with
police decision making.
IO
Investigating Officer
IPCC
Independent Police Complaints Commission
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IPLDP
Initial Police Learning Development Programme 
IT
Information Technology
MAPPA
Multi-Agency Public Protection Arrangement. The partnership
arrangements required under the Criminal Justice Act 2003 to assess
and manage the risks posed by sexual and violent offenders.
Market analysis
Market analysis aims to identify an existing or emerging criminal
market around a commodity or service, and can be used to describe
any criminal market at any level.
Materials
The definition of material used throughout this document is taken
from the CPIA Code of Practice under Part II of the Act:
Material is material of any kind, including information and
objects, which is obtained in the course of a criminal
investigation and which may be relevant to the investigation;
Material may be relevant to an investigation if it appears to an
investigator, or to the officer in charge of an investigation, or to
the disclosure officer, that it has some bearing on any offence
under investigation or any person being investigated, or on the
surrounding circumstances of the case, unless it is incapable of
having any impact on the case.
MC
Magistrates’ Court
MG3
Report to Crown Prosecutor for Initial Charging Decision
MG11
Witness statement
MIM
Murder Investigation Manual
MIR 
Major Incident Room
MIRSAP
Major Incident Room Standardised Administrative Procedures
MMS
Multimedia Messaging Service
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MO
Modus Operandi
MPB
Missing Persons Bureau
NCALT MLE
National Centre for Applied Learning Technologies, Managed
Learning Environment. The National Centre for Applied Learning
Technologies (NCALT) is a collaboration between the National
Policing Improvement Agency (NPIA) and the Metropolitan Police
Service (MPS). NCALT produces and delivers local and national
e-learning and immersive learning solutions for the Police Service.
The Managed Learning Environment (MLE) is NCALT's online
learning delivery platform. It is available to the 43 forces of England
and Wales and other agencies under licence. For further information
see http://www.ncalt.com
NCRS
National Crime Recording Standard
Network analysis
Network analysis provides an understanding of the nature and
significance of the links between people who form criminal networks,
and organisations that interrelate. It also assesses the strengths and
weaknesses of criminal groups or organisations.
NID 
The National Injuries Database is part of the NPIA’s Specialist
Operational Support and advises serious crime investigations on the
analysis and interpretation of wounds and weapon recognition. 
The NID focuses mainly on victims’ injuries and is used as a reference
tool to identify comparable cases. This enables the establishment of a
possible cause for a victim's unknown wound. It can also show specific
injury patterns caused by identified weapons. The NID is linked to the
Serious, Sexual Assault and Attempted Murders Database.
NIM
National Intelligence Model. NIM is a business model for law
enforcement. It takes an intelligence-led approach to policing. 
All forces in England and Wales were required to implement NIM 
to national minimum standards from April 2004.
NOS
National Occupational Standards
Occupational standards describe the skills, knowledge and
understanding needed to undertake a particular task or job to a
nationally recognised level of competence.
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NPIA
The National Policing Improvement Agency was established under
the Police and Justice Act 2006 and was set up to provide support
and expertise to the Police Service in England and Wales.
NSA
National Strategic Assessment provides an annual overview of 
the current, emerging and long-term picture of crime and policing 
in the UK. It is commissioned by the Association of Chief Police
Officers (ACPO)
NTAC
National Technical Assistance Centre
Operational intelligence assessment
Operational intelligence assessment (OIA) is a method of ensuring
that investigations remain focused on their original objectives. OIA
identifies if there is diversification from the agreed objective, and is
best applied to any medium to long-term investigation. OIAs can
help guide investigative activities, focus decisions on resources and
identify priorities for the gathering of intelligence.
PAC
Police Action Checklists are used in the training of police officers.
The PAC identifies a number of real situations that each student
officer needs to have experienced to demonstrate that they have a
reasonable understanding of how to operate on independent patrol.
Student officers will not move to the independent patrol stage until
they have completed the checklist.
PACE 
Police and Criminal Evidence Act 1984
PDF
Personal Descriptive Form
PDR 
Personal Development Review
PEACE
PEACE is an interviewing model. 
P – Preparation and Planning; E – Engage and Explain;
A – Account Clarification and Challenge; C – Closure; E – Evaluation. 
PI 
Public Interest
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PII
Public Interest Immunity
PIMS
Police Informant Management System
PIP
Professionalising Investigation Programme
PNC
Police National Computer
PND
Police National Database
PNLD
Police National Legal Database
PNSC
Police National Search Centre (now part of NPIA)
POCA 
Proceeds of Crime Act 2002
Policing Professional Framework
The Policing Professional Framework (PPF) is a series of national
standards and guidelines managed by Skills for Justice. It enables
forces and individuals to improve quality and consistency of
performance and behaviour in jobs throughout the Police Service.
The framework includes a library of activities linked to national
standards which describe what is to be done, a behavioural
framework detailing how the role is to be undertaken, and profiles 
for most police roles and many staff roles.
Police Service partners
The 1998 Crime and Disorder Act established partnerships between
the police, local authorities, probation service, health authorities, the
voluntary sector, and local residents and businesses. The only parties
legally required to act in a Community Safety Partnership are the
‘responsible authorities’ – police and police authority, the local
council and the fire, health and probation services.
POLKA 
Police Online Knowledge Area
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PolSA 
Police Search Advisers are officers who attend the Police National
Search Centre (PNSC) and receive training in all search-related
matters. They qualify at the conclusion of this training as a PolSA 
and can then advise investigators on all aspects of searching.
PRC 
Policing and Reducing Crime
Prima Facie 
Evidence that is sufficient to raise a presumption of fact or to
establish the fact in question unless rebutted.
Problem profile 
A problem profile is a report produced after a detailed investigation 
of a problem faced in order to obtain a greater understanding of an
established or emerging crime or incident series and problem location.
PSNI
Police Service of Northern Ireland
QC
Queens Counsel
QUEST 
Querying Using Extended Search Techniques. This is a function of the
Police National Computer. 
RA
Regional Advisers
RAIU
Research, Analysis and Information Unit
RDS
Research, Development and Statistics Directorate
RIPA 
Regulation of Investigatory Powers Act 2000
Royal Commission Inquiries
Royal Commission inquiries provide the Government with advice and
information from expert and lay opinion outside the Civil Service.
SARC
Sexual Assault Referral Centre
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SCAS
The Serious Crime Analysis Section is part of the NPIA. It is made up
of crime analysts and specialist police staff who analyse crimes
under specific criteria – essentially rape and serious sexual assaults
and motiveless or sexually motivated murder cases.
SFO
Serious Fraud Office
SIO
Senior Investigating Officer
SMS
Short Messaging Service
SOC
Specialist Operations Centre
SOCA
Serious Organised Crime Agency
SOLO 
Sexual Offences Liaison Officer
SOS
Specialist Operational Support
SPoC
Single Point of Contact
STO
Specially Trained Officers
Student Officer Learing in Assessment Portfolio (SOLAP)
SOLAP is focused on recording achievement of the 22 National
Occupational Standards, which underpin elements in the role profile
of a patrol constable based on the Policing Professional Framework.
Every student officer must keep a SOLAP, which will also be the only
accepted method of presenting evidence to gain NVQ awards.
Subject profile 
A subject profile (formerly known as a target profile) is a report
produced during a detailed investigation of a subject (suspect or
victim). It is used to gain a greater understanding of an individual
and to target or protect the individual(s) through prevention,
intelligence and enforcement opportunities. 
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Tactical assessment 
The tactical assessment drives the business of the tactical tasking
and co-ordination group (TT&CG), identifying and monitoring the
progression of the shorter-term issues in a BCU, force or region, in
accordance with the control strategy.
TIC
Taken into Consideration. This is a process which allows offenders to
admit responsibility for other, similar offences they have committed.
These offences will be ‘taken into consideration by the court’. If the
offender does not admit to any offences and sufficient evidence links
them to an offence at a later stage, they can be charged with these
additional offences.
TIE
Trace, Interview and Eliminate
UK
United Kingdom
UOS
Uniform Operational Support
ViCLAS
Violent Crime Linkage Analysis System is a database holding details
on sexual offences. It can be accessed through the NPIA’s Serious
Crime Analysis Section.
VIPER
Video Identification Parade Electronic Recording
VODS 
Vehicle on Line Descriptive Search (on PNC)
Volume Crime 
Volume crimes are crimes such as burglary and theft of and from
motor vehicles which are widely experienced and make up a high
proportion of all crime.
WCU
Witness Care Units were set up to improve witness attendance in
court. The CPS and the Police Service work together to improve
witness care by supporting witnesses going to court. These units 
were set up as part of the ‘No witness, no justice’ project. For more
information see http://www.cps.gov.uk
YJCEA 1999
Youth Justice and Criminal Evidence Act 1999
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References and Suggested
Further Reading

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ACPO (2004) Practical Guide to Investigative Interviewing.
References
Bramshill: Centrex.
ACPO (2005) Guidance on the Management Recording and
Investigation of Missing Persons. 
Wyboston: NCPE.
ACPO (2005) Guidance on the National Intelligence Model.
Wyboston: NCPE.
ACPO (2005) Major Incident Analysis Manual. Wyboston: NCPE. 
ACPO (2005) Major Incident Room Standardised Administrative
Procedures (MIRSAP). 
Wyboston: NCPE.
ACPO (2006) Guidance on the National Briefing Model.
Wyboston: NCPE.
ACPO (2006) Murder Investigation Manual. Wyboston: NCPE.
ACPO (2006) Practice Advice on Professionalising the Business of
Neighbourhood Policing. 
Wyboston: NCPE.
ACPO (2006) Practice Advice on Search Management and
Procedures. 
Wyboston: NCPE.
ACPO (2007) Guidance on Protecting the Public: Managing Sexual
Offenders and Violent Offenders. 
London: NPIA.
ACPO (2007) Practice Advice: Introduction to Intelligence-Led
Policing. 
London: NPIA.
ACPO (2008) Guidance on the Lawful and Effective Use of Covert
Techniques: The Legal Framework and Covert Operational
Management. 
London: NPIA. [RESTRICTED]
ACPO (2008) Practice Advice on Analysis. London: NPIA.
ACPO (2008) Practice Advice on Evidence of Bad Character, Second
Edition. London: NPIA.
ACPO (2009) Practice Advice on the Management of Priority and
Volume Crime, 
Second Edition. London: NPIA.
ACPO (2010) Advice on the Structure of Visually Recorded Witness
Interviews. 
London: ACPO.
ACPO (forthcoming) Guidance on Managing Operational Risk.
London: NPIA.
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Appendix 2
ACPO National Crime Scene Investigation Board (2007) National
Crime Scene Investigation Manual. 
Issue 1. London: ACPO.
ACPO (n.d.) Good Practice Guide for Computer-Based Electronic
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[Internet]. London: 7Safe. Available from
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computer_evidence_v4_web.pdf 
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ACPO and Her Majesty’s Customs and Excise (1999) Manual of
Standards for Recording and Dissemination of Intelligence Material.
London: ACPO.
Adhami, E. and Browne, D. P. (1996) Major Crime Enquires:
Improving expert support for detectives. 
Police Research Group,
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Armstrong, M. (1997) Management Processes and Functions.
London: Chartered Institute of Personnel and Development. 
Attorney General’s Office (2000) Attorney General’s Guidelines on
Disclosure: Disclosure of Unused Material in Criminal Proceedings.
London: Attorney General’s Office.
Audit Commission (1993) Helping with Enquiries: Tackling Crime
Effectively 
Vol 1 and 2. London: HMSO. 
Black’s (2004) Law Dictionary, Eighth Edition. USA: Thomson West. 
Boyd, R. (2003) Critical Reasoning and Logic. New Jersey, 
USA: Prentice Hall. 
Brooks, I. & Weatherston, J. (1997) The Business Environment:
Challenges and Changes. 
New Jersey, USA: Prentice Hall.
Collier, P.M, Edwards, J.S. and Shaw, D. (2004) Communicating
Knowledge about Police Performance, International Journal of
Productivity and Performance Management, 
53(5), pp 458-467.
Collins (2004) English Dictionary, Sixth Edition. London: Collins.
Criminal Justice System (2004) Criminal Case Management
Framework. 
London: CJS.
Criminal Justice System (2008) Adult Criminal Case Management
Framework, 
Third edition [Internet]. London: CJS. Available from
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mf.cjsonline.gov.uk/ 
[Accessed 20 January 2012]

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Crown Prosecution Service (2010) The Code for Crown Prosecutors
[Internet]. London: CPS. Available from
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Crown Prosecution Service (2011) The Director’s Guidance on
Charging. Guidance to Police Officers and Crown Prosecutors.
Fourth Edition. London: CPS.
Crown Prosecution Service (2005) Disclosure Manual [Internet].
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Europol (1999) Analytical Guidelines (including Inserts). The Hague,
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Friedman, S. (2004) Learning to make more effective decisions:
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Gilbert, J. N. (2001) Criminal Investigation, Fifth Edition. New Jersey,
USA: Prentice Hall.
Gray, D. et al. (2004) Learning Through The Workplace: A guide to
work-based learnings. 
Cheltenham: Nelson Thornes.
Hammond, J., Keeney, R. and Raffia, H. (1998) The Hidden Traps in
Decision Making, Harvard Business Review, 76(5), pp 47-58.
Harrison, E. F. (1975) The Managerial Decision-Making Process.
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Heller, R. (1998) Essential Managers: Making Decisions.
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Home Office (2005) The Victim’s Charter. A statement of service
standards for victims of crime. 
London: Home Office.
Available from
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charter?view=Binary 
[Accessed 20 January 2012]

196
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Appendix 2
Home Office (2006) Vulnerable Witnesses: A Police Service Guide.
London: Home Office. Available from
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Jamieson, A. (2004) A Rational Approach to the Principles and
Practice of Crime Scene Investigation, Science and Justice,
Volume 44 (1) pp 3-7.
Johnston, D. and Hutton, G. (2005) Blackstone’s Police Manual, 
v2: Evidence and Procedure. 
Oxford: Oxford University Press.
Kemshall, H. (2001) Risk Assessment and Management of Known
Sexual and Violent Offenders: A review of current issues. 
Police
Research Series Paper 140. London: Home Office.
Kent Police (2003) Advanced Detective Training: A Model for
Investigation. 
Maidstone, Kent: Kent Police.
McGuire, R. (2002) Decision Making. The Pharmaceutical Journal,
269, pp 647-649.
Ministry of Justice (2011) Achieving Best Evidence in Criminal
Proceedings: Guidance on interviewing victims and witnesses, and
guidance on using special measures
. MoJ:London.
Ministry of Justice (2011) Vulnerable and Intimidated Witnesses: 
A Police Service Guide. 
MoJ:London.
Newburn, T. (ed) (2003) Handbook of Policing. Devon:
Willan Publishing.
Newburn, T and Neyroud, P. (eds) (2008) Dictionary of Policing.
Devon: Willan Publishing.
NPIA (2007) Strategic Debrief: Operation Sumac. London: NPIA.
NPIA (2007) Tactical Debrief: Operation Sumac. London: NPIA.
NPIA (2008) Specialist Operational Support. An introduction to our
services. 
London: NPIA. 
NPIA (2009) Briefing Paper: National Investigative Interviewing
Strategy. 
London: NPIA.
NPIA (2009) Professionalising Investigation Programme (PIP)
[Internet]. London: NPIA.
Available from http://www.npia.police.uk/en/10093.htm
[Accessed 13 January 2012]
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Appendix 2
NPIA (2009) Strategic Debrief: Operation Paris. London: NPIA.
NPIA (2009) Strategic Debrief: Operation Task. London: NPIA.
Osterburg J. W. and Ward R. H. (1992) Criminal Investigation; a
method for reconstructing the past. 
Ohio: Anderson Publishing Co.
Royal Commission on Criminal Justice (1993) Report (CM 2263).
London: HMSO.
Royal Commission on Criminal Procedure (1981) The Investigation
and Prosecution of Criminal Offences in England and Wales: The Law
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London: HMSO.
Right Honourable Lord Justice Auld (2001) A Review of the Criminal
Courts of England and Wales 
[Internet]. London: Ministry of Justice.
Available from http://www.criminal-courts-review.org.uk
[Accessed 20 January 2012] Archive only.
Schick, T. & Vaughn, L. (2002) Chapter 6. Evidence and Inference.
How to Think about Weird Things: Critical Thinking for a New Age
[Internet]. Asia: McGraw-Hill Education. Available from
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Seabrooke, S. and Sprack, J. (1999) Criminal Evidence and
Procedure: The Essential Framework, 
Second Edition.
London: Blackstone Press.
Shepherd, E. and Ede, R (2000) Active Defence.
London: The Law Society.
Skills for Justice (2012) Policing Professional Framework
[Internet]. Available from http://www.skillsforjustice.com/PPF
[Accessed 13 January 2012]
Smith, N. and Flanagan, C. (2000) The Effective Detective:
Identifying the skills of an effective SIO. 
Police Research Series
Paper 122 [Internet]. London: Home Office. Available from
http://www.homeoffice.gov.uk/rds/prgpdfs/fprs122.pdf
[Accessed 20 January 2012]
Stewart, E. (1998) Operational Decision Making, Police Research 
and Management, 2
(3), pp 73-86. 
The Law Society (1999) The Guide to the Professional Conduct of
Solicitors, 
Eighth Edition. London: The Law Society.
198
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The Law Society (2003) Law Society’s Code for Advocacy.
London: The Law Society.
Tilley, N. and Ford, A. (1996) Forensic Science and Crime
Investigation, 
Crime Detection and Prevention Paper 73.
London: Home Office.
Torrington, D. and Hall, L. (1995) Personal Management: HRM in
Action, 
Third Edition. London: Prentice Hall.
Tourish, D. and Hargie, O. (2004) Key Issues in Organisational
Communication. 
London: Routledge. 
Townley, L. and Ede, R. (2004) Forensic Practice in Criminal Cases.
London: The Law Society. 
Tsoukas, H. and Mylonopoulos, N. (2004) Organisations as
Knowledge Systems; Knowledge, learning and dynamic capabilities.
Basingstoke: Palgrave Macmillan.
West, A. (2001) A Proposal for an Investigative Science Course:
Any takers? Police Research and Management 5(2), pp 13-22.
ACPO (2001) Guide to Meeting the Policing Needs of Asylum
Suggested
Seekers and Refugees. London: ACPO. 
Further Reading
ACPO (2003) Domestic Burglary National Good Practice and Tactical
Options Guide. 
London: ACPO. 
ACPO (2006) Guidance on the Safer Detention and Handling of
Persons in Police Custody. 
Wyboston: NCPE. 
ACPO (2006) Practice Advice on House-to-House Enquiries.
Wyboston: NCPE. 
ACPO (2007) DNA Good Practice Manual, Third Edition.
London: ACPO. [RESTRICTED]
ACPO (2007) Road Death Investigation Manual. London: NPIA. 
ACPO (2008) Guidance on Casualty Bureau Standard Administrative
Procedures. 
London: NPIA. 
ACPO (2008) Guidance on Investigating Domestic Abuse.
London: NPIA. 
ACPO (2009) Facial Identification Guidance. London: NPIA.
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ACPO (2009) Guidance on Investigating and Prosecuting Rape.
London: NPIA. [PROTECT-INVESTIGATION]
ACPO (2009) Guidance on Investigating Child Abuse and
Safeguarding Children, 
Second Edition. London: NPIA.
ACPO (2009) Manual of Guidance on the Management, Command
and Deployment of Armed Officers. 
London: NPIA.
ACPO (2009) National Strategic Assessment. London: 
NPIA. [RESTRICTED]
ACPO (2010) Guidance on the Management of Police Information,
Second Edition. London: NPIA. 
Adderley, R.W. and Musgrove, P. (2001) Police Crime Recording 
and Investigation Systems – A Users View, Policing: An International
Journal of Police Strategies and Management, 
24 (1) pp 100-114. 
Amey, P., Hale, C. and Mieczkowski, T. (1996) Development and
Evaluation of a Crime Management Mode. 
Police Research Series,
Paper 18. London: Home Office. 
Audit Commission (1996) Detecting a Change: Progress in Tackling
Crime Bulletin. 
London: HMSO. 
Blake, L. and Coupe, R. T. (2001) The impact of single and two
passenger patrols on catching burglars in the act, British Journal of
Criminology, 
41 (2), pp 381-396. 
Bloch, P. B. and Bell, J. (1976) Managing Investigations: The
Rochester system. 
Washington DC: The Police Foundation. 
Bottomley, A. K. and Coleman, C. A. (1980) Police Effectiveness and
the Public: The Limitations of Official Crime Rates, in Clarke, R. V. G
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MA: Lexington Books. 
Brandl, S. G. and Frank, J. (1994) Relationship between Evidence,
Detective Effort, and the Disposition of Burglary and Robbery
Investigations, American Journal of Police, 13 (3), pp 452-465. 
Brockriede, W. and Ehninger, D., Toulmin on Argument:
An Interpretation and Application, The Quarterly Journal of Speech,
pp 44-53.
Brown, D. (1991) Investigating Burglary: The Effects of PACE.
Home Office Research Study 1243. London: Home Office. 
200
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Appendix 2
Burleson, B. R. (1979) On the Foundations of Rationality: Toulmin,
Habermas, and the A Priori of Reason, Journal of the American
Forensic Association 
16 (Fall 1979), pp 112-127. 
Burrows, J. (1986) Burglary: Police Actions and Victims Views. Home
Office Research and Planning Unit, Paper 37. London: Home Office. 
Burrows, J. and Tarling, R. (1982) Clearing Up Crime. Home Office
Research Study 73. London: Home Office. 
Burrows, J. and Tarling, R. (1987) Investigation of Crime in England
and Wales, British Journal of Criminology, 27 (3), pp 229-251. 
Byford, L. (1981) The Yorkshire Ripper Case: Review of the Police
Investigation of the Case by Lawrence Byford, Esq., CBE., QPM.,
Her Majesty’s Inspector of Constabulary [Internet].
London: Home Office. Available from
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information/released-information/foi-archive-crime/1941-
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Chappel, D., Gordon, R. and Moore, R. (1982) Criminal Investigation:
A Selective Literature Review and Bibliography. 
Burnaby, Canada:
Criminology Research Centre, Simon Fraser University.
Clawson, C. and Chang, S. (1977) The Relationship between
Response Delays and Arrest Rates, Journal of Police Science and
Administration, 
5, pp 53-68.
Coupe, T. and Griffiths, M. (1996) Solving Residential Burglary. Crime
Detection and Prevention Series, Paper 77. London: Home Office.
Diez, L. (1995) The Use of Call-Grading: How Calls to the Police are
Graded and Resourced. 
Police Research Series Paper 13. London:
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Duff, P. (1998) Crime Control, Due Process and ‘The Case for the
Prosecution’, British Journal of Criminology, 38 (4), pp 611-615. 
Eck, J. E. (1979) Managing Case Assignments: The burglary
investigation decision model replication.
Washington DC: Police Executive Research Forum.
Eck, J. E. (1983) Solving Crimes: The Investigation of Burglary and
Robbery. 
Washington DC: Police Executive Research Forum. 
Evans, R. (2001) The Importance of Investigation. Jane’s Police
Review, 
Sept 07, 2001.
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Folk, J. F. (1971) Municipal Detective Systems – A Quantitative
Approach. 
Technical Report No 55. Massachusetts, USA:
Massachusetts Institute of Technology. 
Forensic Science Service (2003) Retention of Case Material: A
Memo of Understanding between the Forensic Science Service and
ACPO. 
London: ACPO.
Forensic Science Service (2004) The Scenes of Crime Handbook.
Chorley, Lancashire: Forensic Science Services.
Forensic Science Service (n.d) Safe Recovery of Firearms and
Submission of Recovered Firearms onto National Forensic Firearms
Intelligence Database (NFFID). 
Birmingham: Forensic Science Services.
Francis, B. et al (2004) Using homicide data to assist murder
investigations. 
Home Office Online Report 26/04.
London: Home Office. Available from
http://www.homeoffice.gov.uk/rds/pdfs04/rdsolr2604.pdf
[Accessed 20 January 2012]
Gaines, L. K. (1983) Case Screening in Criminal Investigations: a case
study of robberies, Police Studies 6(2), pp 22-29.
Gaylor, D. (2005) Getting away with murder The Re-investigation of
historic undetected Homicide. 
London: Home Office. 
Gill, M. et al (1996) The Crime Allocation System: Police
Investigations into Burglary and Auto Crime. 
Police Research Series
Paper 16. London: Home Office. 
Greenberg, B. et al (1975) Felony Investigation Decision Model:
An Analysis of Investigative Elements of Information.
Washington DC, USA: US Government Printing Office.
Greenwood, P. (1970) An Analysis of the Apprehension Activities of
the New York City Police Department. 
California, USA: Rand.
Greenwood, P. and Petersilia, J. (1975) The Criminal Investigation
Process – Volume I: Summary and Policy Implications
. California,
USA: Rand.
Greenwood, P., Chaiken, J. and Petersilia, J. (1977) The Criminal
Investigation Process
. Lexington, USA: DC Heath and Co.
Griffiths, B.(2003) Investing in Investigation, Policing Today, 9(2),
pp 23-25.
202
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Appendix 2
Grubin, D. Kelly, P. Brunsdon, C (2001) Linking serious sexual
assaults through behaviour 
[Internet]. Home Office Research Study
215. London: Home Office. Available from
http://www.homeoffice.gov.uk/rds/pdfs/hors215.pdf
[Accessed on 20 January 2012]
Harris, J. and Grace, S. (1999) A question of evidence? Investigating
and prosecuting rape in the 1990s 
[Internet]. Home Office Research
Study 196. London: Home Office. Available from
http://www.homeoffice.gov.uk/rds/pdfs/hors196.pdf
[Accessed 20 January 2012] 
HC653 (2004) The Bichard Inquiry Report. London: TSO.
Her Majesty’s Crown Prosecution Service Inspectorate (2002)
A report on the joint inspection into the investigation and
prosecution of cases involving allegations of rape. 
London: HMIC.
HMIC (2000) On the Record: Thematic Inspection Report on Police
Crime Recording, the Police National Computer and Phoenix
Intelligence System Data Quality. 
London: HMIC. Available from
http://www.hmic.gov.uk/publication/on-the-record/
[Accessed 13 January 2012]
HMIC (2000) Policing London “Winning Consent” A Review of
Murder Investigation and Community & Race Relations Issues in the
Metropolitan Police Service. 
London: HMIC.
HMIC (2000) Under the Microscope. London: HMIC.
HMIC (2002) Inspection Sub-protocol for Crime Recording/Audit.
London: HMIC.
HMIC (2002) Under the Microscope Refocused. London: HMIC.
HMIC (2004) A Report on the Investigation by Cambridgeshire
Constabulary into the Murders of Jessica Chapman and Holly Wells
at Soham on 4 August 2002: Summary of conclusions and
recommendations. 
Available from
http://www.hmic.gov.uk/inspections/specialist-inspections/a-
report-on-the-investigation-by-cambridgeshire-constabulary-
jessica-chapman-and-holly-wells 
[Accessed 13 January 2012] 

Home Office (n.d.) Crime in England and Wales 2006/2007.
London: Home Office. Available from
http://rds.homeoffice.gov.uk/rds/crimeew0607.html
[Accessed 20 January 2012]
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Appendix 2
Home Office and ACPO (2003) National Vehicle Crime Guidelines
and Tactical Options. 
Home Office Police Science Technology
Strategy 2004-2009. London: Home Office.
Home Office (2007) UK Action Plan on Tackling Human Trafficking.
London: Home Office. Available from
http://www.ungift.org/doc/knowledgehub/resource-
centre/Governments/UK_Action_Plan_to_Combat_Human_Traf
ficking_en.pdf 
[Accessed 13 January 2012]

Horwath, F. Meesig, R. T. and Lee, Y. H. (2002) National Survey of
Police Policies and Practices Regarding the Criminal Investigations
Process: Twenty-Five Years after Rand. 
USA: National Criminal Justice
Reference Service. 
Irvin, B. (1986) Police Interrogation. Royal Commission on Criminal
Procedure Research Study No.2. London: HMSO. 
Isaacs, H. (1967) A Study of Communications, Crimes and Arrests in
a Metropolitan Police Department. 
Task Force Report: Science and
Technology. Washington DC, USA: UN Government Printing Office. 
Jacobson, J., Maitland, L. and Hough, M. (2003) The Reducing
Burglary Initiative: Investigating Burglary. 
Home Office Research
Study 264. London: Home Office.
Jacobson, J., Maitland, L. and Hough, M. (2003) Investigating
burglary: findings from the Reducing Burglary Initiative.
Home Office Findings 181. London: Home Office.
Available from http://www.homeoffice.gov.uk/rds/pdfs2/r181.pdf
[Accessed 20 January 2012]
Jolowicz, C. (1994) Managing Demand on the Police: An Evaluation
of a Crime Line. 
Police Research Series Paper 9. London: Home Office
Police Research Group.
Kind, S. (1986) The Science of Crime Investigation.
London: Crown Publishing. 
Kind, S. (1987) The Scientific Investigation of Crime. Harrogate:
Forensic Science Service.
Leisham, F., Loveday, B. and Savage, S. (Eds) (2000) Core Issues in
Policing, 
Second Edition. Harlow, UK: Longman.
204
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Appendix 2
Levi, M. and Osofsky, L. (2005) Investigating, seizing and
confiscating the proceeds of crime. 
Crime Detection and Prevention
Series. Paper No. 61. London: Home Office Police Research Group.
Available from
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[Accessed 20 January 2012]
Laming, H. (2003) The Victoria Climbié Inquiry Report. London: TSO.
Macpherson, W. (1999) The Stephen Lawrence Inquiry, Chair.
London: TSO. Available from http://www.archive.official-
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[Accessed 20 January 2012]
Maguire, M. (1999) Policing by Risks and Targets: Some Dimensions
and Implications of Intelligence-Led Crime Control, Policing and
Society, 
9, pp 315-336.
Maguire, M. and John, T. (2005) Intelligence, Surveillance and
Informants: Integrated Approaches. 
Crime Detection and Prevention
Series. Paper 64. London: Home Office Police Research Group.
Available from http://www.homeoffice.gov.uk/rds/prgpdfs/
fcdps64.pdf 
[Accessed 20 January 2012] 

Marlow, A. et al (1989) The Practice of Detective Work in a Country
Force, Criminologist, 13(3), pp 130-135.
Martin, S. E. and Sherman, L. W. (1986) Police Foundation Report:
Catching Career Criminals: 
The Washington, DC, Repeat Offender
Project. London: Police Foundation.
Mawby, R. I. (1979) Policing the City. Westmead, UK: Saxon House. 
McConville, M. and Balwin, J. (1982) The Role of Interrogation in
Crime Discovery and Conviction, British Journal of Criminology,
22 (1), pp 165-175.
McCulloch, H. (1996) Police use of forensic science. Home Office
Research Series Paper 19. London: Home Office Police Research Group.
Mitchell, B. (1983) Confessions and police interrogation of suspects.
Criminal Law Review, pp 596-604. 
Modern Records Centre (1981) Royal Commission on Criminal
Procedure 1978-81, 
[Internet]. Available from
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[Accessed 20 January 2012]
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Nicol, C. et al (2004) Reviewing murder investigations: an analysis
of progress reviews from six police forces 
[Internet]Home Office
Findings 218. London: Home Office. Available from
http://library.npia.police.uk/docs/hofindings/r218.pdf 
[Accessed 20 January 2012]
Nicol, C. et al (2004) Reviewing murder investigations: an analysis
of progress reviews from six police forces 
[Internet]Home Office
Online Report 25/04. London: Home Office. Available from
http://www.homeoffice.gov.uk/rds/pdfs04/rdsolr2504.pdf
[Accessed 20 January 2012]
Pate, T., Bowers, R.A. and Parks, R. (1976) Three approaches to
criminal apprehension in Kansas City: an evaluation report.
Washington DC: Police Foundation.
Pease, K. (1998) Repeat Victimisation: Taking Stock. Crime
Detection and Prevention Series Paper 90. London: Home Office
Police Research Group.
Pengelly, R. (2000) In Search of the Effective Detective. Police
Magazine, 
pp 13-15.
Pike, G., Brace, N. and Kynan, S. (2002) The Visual Identification of
Suspects: Procedures and Practice. 
Home Office Briefing Note 2/02.
London: Home Office.
Rix, B. (2004) The contribution of shoemark data to police
intelligence, crime detection and prosecution. 
Home Office Findings
236. London: Home Office. Available from
http://www.homeoffice.gov.uk/rds/pdfs04/r236.pdf
[Accessed 20 January 2012]
Sentamu, Rt Revd J. et al (2002) The Damilola Taylor Murder
Investigation Review: The Report of the Oversight Panel. 
Presented to
Sir John Stevens QPM DL, Commissioner of Police of the Metropolis.
Available from http://image.guardian.co.uk/sys-
files/Guardian/documents/2002/12/09/damilola.pdf
[Accessed 20 January 2012]
Sherman, L. W. and Eck, J. E. (2002) ‘Policing for Crime Prevention’
in Sherman, L. W., et al (eds) Evidence-Based Crime Prevention.
London: Routledge.
Smith, J. (2003) The nature of personal robbery. Home Office
Research Study 254. London: Home Office.
206
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Appendix 2
Softley, P. et al (1980) Police Interrogation: An Observational Study
in Four Police Stations. 
Home Office Research Study 61.
London: Home Office Research Unit.
Steer, D. (1980) Uncovering Crime: The Police Role. Royal Commission
on Criminal Procedure Research Study (7). London: HMSO.
Stevens, J. M. and Stipak, B. (1982) Factors Associated With Police
Apprehension Productivity, Police Science and Administration,
10 (1), pp 52-57.
Stockdale, J. and Gresham, P. (1995) Combating Burglary: An
Evaluation of Three Strategies. 
Crime Detection and Prevention
Series Paper 59. London: Home Office.
Stockdale, J. and Gresham, P. (1998) Tackling Street Robbery:
A comparative Evaluation of Operation Eagle Eye. 
Crime Detection
and Prevention Series Paper 87. London: Home Office.
The Shipman Inquiry (2005) The Shipman Inquiry: Independent
Public Inquiry into the issues arising from the case of Harold Fredrick
Shipman. 
London: The Shipman Inquiry.
Available from http://www.shipman-inquiry.org.uk/home.asp
[Accessed 20 January 2012]
Tilley, N. et al (2004) Problem-solving street crime: practical lessons
from the Street Crime Initiative
. London: Home Office.
Available from
http://www.homeoffice.gov.uk/rds/pdfs04/pssc.pdf
[Accessed 20 January 2012]
Waegel, W. B. (1982) Patterns of Police Investigation of Urban
Crimes, Journal of Police Science and Administration, 10 (4),
pp 452-465.
Webb, B., Tilley, N. and Ford, A. (Ed) Forensic Science and Crime
Investigation. 
Police Research Group Crime Detection and Prevention
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http://www.homeoffice.gov.uk/rds/prgpdfs/fcdps73.pdf
[Accessed 20 January 2012]
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[Accessed 20 January 2012]
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Briefing Models –
IIMARC and SAFCOM

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Briefing Model 1: IIMARC
INFORMATION
What is the ‘action’ about?
This will include the following considerations:
This can be compared to the 
• When will it commence?
‘Situation’ in the acronym
SAFCOM.
• How long will it last?
• Where is the venue?
• Is the action covered by legislation?
• Are any other agencies involved and do they
have specific legal responsibilities? 
INTENTION
What is the intention?
This will detail what needs to be achieved as far
This can be compared to the
as is reasonably practicable causing least
‘Aim’ in the acronym SAFCOM.
disruption to normal community life, returning to
normal as soon as possible.
METHOD
How will the intention 
This will include the following considerations:
be achieved?
• What is the command structure, who is in
command and where will they be during
the action?
• There must be clear tasking, detailing who is
responsible for what;
• Is there a need for a rendezvous point (RVP)
or marshalling area and cordons, if so where
are they to be sited?
• What routes should vehicles take and where
must they be parked, are there maps/sketch
plans available?
• What is the policy for dealing with
arrests/prisoners, who will deal with them
and where should they be taken?
• Is there any liaison with any specialist police
agencies or outside agencies and what is
their role?
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ADMINISTRATION
What are the administrative 
The list of considerations here is endless but may
issues surrounding the
include the following:
action?
• Briefing – where will it take place, briefing
aids required, who will attend etc?
• Security and Disclosure – who needs to
know, unused and sensitive material,
communication etc?
• Contingency Plans – what could go wrong,
what will happen then etc;
• Custody issues – location, interviewing,
interpreters etc;
• Personnel – start/finish times and locations,
transport, overtime, refreshment, toilet
facilities, equipment/tools, protective
clothing, welfare etc;
• Media Issues – press liaison, press 
releases etc;
• Intelligence – information known,
information to be gained etc; 
• Legal Issues – legislation handouts,
warrants, authorities etc. 
RISK
What are the weaknesses
Issues will include the following considerations:
and threats and what could
• What are the health and safety/duty of care
go wrong?
issues in respect of operational team,
support services, the public, suspect?
• How can weaknesses/threats be lessened or
eliminated, what are the plans to cope with
them?
• Are staff deployed in sufficient numbers, are
they adequately trained/equipped, have they
been properly briefed?
• Is there a need for a community care
assessment plan to minimise adverse effects
Note:
on the local community?
• For larger operations
• If anything goes wrong, what would need
consideration must be given to
to be done, how could existing resources be
writing a health and safety risk
diverted, could they cope, could a change of
assessment.
purpose be achieved, could resources
employed within the operation be readily
deployed at short notice, is there a need for
a reserve etc?
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COMMUNICATIONS How will communication 
Issues will include the following considerations:
be maintained throughout
• Security implications;
the action?
• Radios – type, channel, spare batteries, call
signs, radio silence etc;
• Mobile Phones, contact telephone numbers
and loud hailers. Will all communication go
through the Operational Commander or the
control room?
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Briefing Model 2: SAFCOM
SITUATION
What is the problem?
What is the situation or problem?
This can be compared to the
‘Information’ in the acronym
The officer needs to be able to give a clear and
‘IIMARC’
factual outline.
AIM
What is my aim?
What is the officer’s aim in addressing the
This can be compared to the
situation?
‘Intention’ in the acronym
‘IIMARC’
The officer requires a clear aim, how can an
operation be planned without a clear idea of
what it is supposed to achieve? 
FACTORS
What are all the factors 
This is a risk assessment.
that make up or contribute
to this problem?

The officer needs to consider:
• What factors may affect the operation?
• What steps need to be taken to reduce risk,
if that is possible?
• What resources will be required?
CHOICES
What are the various
The officer is expected to examine all possible
solutions?
ways of addressing the situation and conduct an
assessment/analysis of each method.
OPTION
What is my preferred option?
Having examined the available choices the officer
This can be compared with the
needs to decide on the preferred option and be
‘Method’ in the acronym
able to explain why.
‘IIMARC’
• Is it effective?
• Is it proportionate?
• Does it represent best value?
• Is it achievable?
MONITORING
How will the preferred
The officer needs to have a method of
option be monitored in 
monitoring whether the preferred option is
order to ensure the aim 
achieving the aim.
is achieved?
• How will success be measured?
• Mobile phones, contact telephone numbers
and loud hailers.
• Will all communications go through 
the Operational Commander or the 
control room?
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