Forensic Examination and Interpretation of Tool Marks

The Forensic Examination and Interpretation of Tool
Marks brings together key techniques and developments in
the field of tool marks in forensic science and explains clearly
how tool mark analysis can be used within forensic
investigation.

The purpose of this book is to bring together as much of this
information as possible in an accessible manner. The book deals
with all aspects of tool mark evidence from crime scene to
courtroom. The examination of a wide variety of different tool
marks are discussed, including those made by specific tools such as
saws and in complex materials such as bone.

The general principles and techniques used in tool mark
examinations can also be applied to some other closely related
fields. Therefore, sections on the examination of manufacturing
marks, including those on plastic film items, and physical fit
comparisons are also included.

The book will be of interest to a wide range of people and
not just to tool mark examiners and people studying forensic
science. It will be of use to crime scene examiners, officers
investigating crimes where tool marks are found and members of the
legal professions.

• Brings together key techniques and developments within the
  field of tool mark investigation.

• Includes material on examining tool marks at the crime scene
  and in the laboratory, interpretation and evaluation issues and how
  tool mark evidence should be presented in court.

• Covers specialized tool mark examinations, manufacturing marks,
  including those on plastic film items, and physical fits.

• Includes a large range of illustrations and photographs.

• Invaluable reference for practicing forensic scientists,
  students of forensic sciences, members of the legal professions and
  crime scene investigators, enabling them to recognise the
  importance of tool marks within an investigation.

• An extremely valuable resource in the on-going debate regarding
  the evidential value of tool marks in court.

• Part of the 'Essentials in Forensic Science'
  book series.

Autorentext

DAVID BALDWIN Baldwin Forensic Consultancy, Formerly of Forensic Science Service Ltd, London

JOHN BIRKETT Formerly of Forensic Science Service Ltd, London

OWEN FACEY Staffordshire University

GILLEON RABEY Formerly of Forensic Science Service Ltd, London

Zusammenfassung

The Forensic Examination and Interpretation of Tool Marks brings together key techniques and developments in the field of tool marks in forensic science and explains clearly how tool mark analysis can be used within forensic investigation.

The purpose of this book is to bring together as much of this information as possible in an accessible manner. The book deals with all aspects of tool mark evidence from crime scene to courtroom. The examination of a wide variety of different tool marks are discussed, including those made by specific tools such as saws and in complex materials such as bone.

The general principles and techniques used in tool mark examinations can also be applied to some other closely related fields. Therefore, sections on the examination of manufacturing marks, including those on plastic film items, and physical fit comparisons are also included.

The book will be of interest to a wide range of people and not just to tool mark examiners and people studying forensic science. It will be of use to crime scene examiners, officers investigating crimes where tool marks are found and members of the legal professions.

• Brings together key techniques and developments within the field of tool mark investigation.
• Includes material on examining tool marks at the crime scene and in the laboratory, interpretation and evaluation issues and how tool mark evidence should be presented in court.
• Covers specialized tool mark examinations, manufacturing marks, including those on plastic film items, and physical fits.
• Includes a large range of illustrations and photographs.
• Invaluable reference for practicing forensic scientists, students of forensic sciences, members of the legal professions and crime scene investigators, enabling them to recognise the importance of tool marks within an investigation.
• An extremely valuable resource in the on-going debate regarding the evidential value of tool marks in court.
• Part of the 'Essentials in Forensic Science' book series.

Inhalt

About the Authors xi

Series Foreword: Essentials of Forensic Science xv

Foreword xvii

Preface xxi

About the Companion Website xxv

1 Introduction 1

1.1 Overview of contents 1

1.2 A brief history of tool marks 4

1.3 General aspects of marks' comparison 7

1.4 Training requirements for examiners 8

1.5 Good forensic practice 10

1.6 Examination and comparison strategy 11

1.6.1 Analysis 11

1.6.2 Comparison 12

1.6.3 Evaluation 12

1.6.4 Verification 12

1.7 Environment and equipment 13

1.7.1 Basic requirements 13

1.7.2 Examiner's 'toolbox' 14

1.7.3 Test mark and casting materials 14

1.7.4 Larger equipment 17

1.7.4.1 The comparator 18

1.8 Quality assurance 22

1.9 A brief summary 23

References 24

2 Tool Manufacture 25

2.1 Introduction 25

2.2 Working with metal 28

2.3 Creating a tool 'blank' 29

2.3.1 Forging 30

2.3.2 Blanking and shearing 31

2.3.3 Metal cutting operations 32

2.4 Finishing processes 34

2.5 Wear, corrosion and damage 45

References 51

3 Scene Examination 53

3.1 Examining and recording the scene 53

3.2 General preliminaries 54

3.2.1 Verifying the circumstances 54

3.2.2 Recording the scene 54

3.2.3 Scene to scene linking 55

3.2.4 Packaging 55

3.3 Forced entry markslevering 56

3.3.1 Recovery of levering marks 58

3.4 Forced entry marksother 63

3.4.1 Hammer-type attack 64

3.4.2 Gripping tool attacks 65

3.4.3 Motor vehicle entry 66

3.5 Entry by cutting 67

3.5.1 Padlock removal 68

3.5.2 Breached security systems 69

3.6 Theft of metal 72

3.7 Examination of machines 73

3.8 Pathology samples 74

3.9 Collecting suspect tools 77

References 79

4 Initial Laboratory Examination 81

4.1 General preliminaries 81

4.1.1 Receiving items 81

4.1.2 Planning the examination 82

4.1.3 Preparing for the examination 84

4.1.4 Collecting the items 84

4.1.5 Decontamination of item packaging 84

4.1.6 Operating procedures 84

4.1.7 Recording and opening the packaging 85

4.1.8 Description of the item 86

4.1.9 Examination of the item 86

4.2 Mainly impressed marks 86

4.2.1 Levering marks 87

4.2.2 Impact marks 89

4.2.3 Gripping marks 89

4.2.4 The tool(s) 90

4.3 Mainly dynamic marks 91

4.3.1 Levering marks with striations 92

4.3.2 Cutting and stabbing marks 92

4.4 Saw marks 99

4.5 Post-mortem samples 105

4.6 Alphanumeric punches 108

4.7 Using tool marks for intelligence purposes 111

4.7.1 Type and size of tool 111

4.7.2 Scene-to-scene linking without a tool 111

4.7.3 Scene-to-scene linking using a tool recovered from a scene 112

4.7.4 Linking suspect's tool(s) to previously unsuspected scenes 112

4.7.5 Setting up a database 112

References 113

5 Detailed Laboratory Examination 115

5.1 First considerations 115

5.2 Presentation of material to the comparator 116

5.3 Impressed marks 119

5.4 Marks with striations 123

5.4.1 Sliding marks 124

5.4.2 Double-bladed cutting tools 128

5.4.3 Stab marks (in tyres and bones) 131

5.5 Saw marks 136

5.5.1 Initial and final cuts 136

5.5.2 Sawn ends 137

5.6 Specialised marks 139

5.6.1 Alphanumeric punches 139

5.6.2 Drill marks 143

5.6.3 Slide hammers 144 &...