Vincent J. Desiderio is the Hazardous Materials Program Specialist for the United States Postal Inspection Service-Security Group, Washington, D.C. Chris E. Taylor is a Forensic Chemist at the Defense Forensic Science Center-US Army Criminal Investigation Laboratory in Forest Park, Georgia. Niamh Nic Daéid, PhD, is Professor of Forensic Science and Director of the Leverhulme Research Centre for Forensic Science, School of Science and Engineering, University of Dundee, Scotland.

• List of Contributors xvPreface xvii1 Trace Evidence Recognition, Collection, and Preservation 1Ted R. Schwartz, Daniel S. Rothenberg, and Brandi L. Clark1.1 Introduction 11.2 Theories of Transfer and Persistence 11.2.1 Locard’s Exchange Principle 11.2.2 Primary, Secondary, Tertiary, etc. Transfers 21.2.3 Non-contact Transfers 41.2.4 Patterns Due to Contact 41.2.5 Factors Affecting the Likelihood of a Transfer 51.2.6 Factors Affecting Persistence 51.3 Proper Evidence Handling Practices 61.3.1 Proper Clothing to Wear and Why 71.3.2 Other Techniques to Avoid Contamination and Loss 71.4 Recognition, Collection, and Preservation of Trace Evidence at the Crime Scene 81.4.1 Searching for Relevant Trace Evidence 91.4.1.1 Visible Trace Evidence 91.4.1.2 Invisible Trace Evidence 91.4.2 Documentation 91.4.3 Collection 101.4.3.1 Collecting the Entire Item Containing Potential Trace Evidence 111.4.3.2 Picking with a Gloved Hand or Tweezers 131.4.3.3 Collecting Invisible Trace Evidence 141.4.3.4 Tape Lifting 141.4.3.5 Vacuum Sweeping 151.4.3.6 Tape Lifting vs. Vacuum Sweeping: Which Method to Use? 161.4.3.7 Other Techniques 161.4.4 Taking Known Exemplars and Alibi Samples 171.4.5 Collection of Trace Evidence from a Body 181.4.6 Preserving Evidence and Maintaining the Chain of Custody 19Checklist: Crime Scene Procedures 19Components of a Crime Scene Kit for Trace Evidence Collection 201.5 Recognition, Collection, and Preservation of Trace Evidence in the Laboratory 211.5.1 Workspace Preparation 21Checklist: Preparation of Examination Area in the Laboratory 211.5.2 Evidence Examination Considerations 221.5.3 Initial Examination Considerations 22A Note Regarding Evidence Handling and Potential DNA Contamination 221.5.4 Evidence Description 231.5.5 Macroscopic Evidence Examination 231.5.6 Stereomicroscopic Examination 231.5.7 Additional Documentation 241.5.8 The Collection of Trace Evidence from Items in the Laboratory 251.5.9 Collection Techniques 251.5.9.1 Picking off Observed Trace Evidence 251.5.9.2 Shaking/Scraping 261.5.9.3 Tape Lifting 271.5.9.4 Vacuum Sweeping 271.5.9.5 Combinations of the Above Methods 281.5.10 Taking Known Exemplar Samples 28Checklist: Evidence Examination in the Laboratory 281.6 Summary 29Acknowledgments 29References 29Further Reading 302 Polarized Light Microscopy for the Trace Evidence Examiner 32Andrew M. Bowen2.1 Introduction 332.2 The Nature of Light 342.2.1 Reflection 352.2.2 Refraction 362.2.3 Dispersion 402.2.4 Temperature Coefficient of Refractive Index 412.2.5 Absorption of Light 412.2.6 Other Interactions Between Light and Matter 412.3 Light Microscopy 422.3.1 Image Formation in a Compound Light Microscope 422.3.2 Numerical Aperture and Resolution 452.4 Introduction to Crystallography 552.4.1 Symmetry 552.4.2 Crystal Point Groups 572.4.3 Six Crystal Systems 582.4.3.1 Cubic (Isometric) System 582.4.3.2 Tetragonal System 602.4.3.3 Hexagonal System 602.4.3.4 Orthorhombic System 622.4.3.5 Monoclinic System 622.4.3.6 Triclinic System 632.4.4 Crystal Morphology 642.4.4.1 Miller Indices 652.4.4.2 Crystal Forms and Crystal Habit 672.4.4.3 Crystal Morphology Through the Light Microscope 682.5 Introduction to Optical Crystallography 692.5.1 Optics of Isotropic Substances 692.5.2 Optics of Uniaxial Substances 752.5.3 Optics of Biaxial Substances 842.5.3.1 Optic Axial Plane and Optic Normal 882.5.3.2 Acute Bisectrix, Obtuse Bisectrix, Optic Sign, and Optic Axial Angle 902.5.3.3 Optical Orientation 912.5.3.4 Dispersion in Biaxial Crystals 932.6 Measurement of Optical Properties 942.6.1 Measurement of Refractive Index Values: Isotropic Substances 952.6.1.1 Becke Line Immersion Method 972.6.1.2 Single Variation Method 992.6.1.3 Emmons Double Variation Method 1002.6.2 Measurement of Refractive Indices in Uniaxial Substances 1002.6.3 Measurement of Refractive Index in Biaxial Substances 1052.6.4 Retardation 1072.6.5 Birefringence 1132.6.6 Extinction Characteristics 1202.6.7 Use of Compensators and Sign of Elongation 1292.6.8 Conoscopic Observations of Uniaxial Substances 1342.6.9 Conoscopic Observations on Biaxial Substances 1422.6.10 Updated Measurement of Refractive Index Values: Uniaxial Substances 1502.6.11 Updated Measurement of Refractive Index Values: Biaxial Substances 1512.6.12 The Spindle Stage 1512.7 Identification of an Unknown Using Optical Properties 1522.7.1 Applications of Light Microscopy to Trace Evidence 155References 1563 Paints and Polymers 157Robyn B. Weimer, Diana M. Wright, and Tamara Hodgins3.1 Introduction to the Paint and Polymer Discipline 1573.2 Overview of Polymer Chemistry 1593.2.1 Introduction to Polymers 1593.2.2 Polymer Synthesis 1593.3 Overview of Coatings 1603.3.1 Chemistry and Terminology of Coatings 1603.3.1.1 Binders 1613.3.1.2 Pigments 1613.3.1.3 Additives 1633.3.1.4 Volatile Components 1633.3.2 Manufacturing Considerations 1633.3.3 Application Processes 1643.3.3.1 Spraying 1643.3.3.2 Dipping 1653.3.3.3 Electrodeposition 1653.3.4 Types of Coatings and End Uses 1663.3.4.1 Automotive Coatings 1663.3.4.2 Architectural Coatings 1713.3.4.3 Vehicular Non-automotive Coatings 1733.3.4.4 Tool Coatings 1743.3.4.5 Other/Specialty Coatings 1743.3.5 Other Polymeric Materials 1773.3.5.1 Buttons, Hair Beads, Jewelry, and Synthetic Fingernails 1773.3.5.2 Gasoline Cans 1773.3.5.3 Plastic Bags 1783.3.5.4 Gloves 1783.3.5.5 Automotive Parts and Panels 1783.3.5.6 Decals 1783.3.5.7 Paintballs 1793.3.5.8 Glitter 1793.3.5.9 Foam 1793.4 Forensic Examination 1803.4.1 Recognition, Collection, and Preservation 1803.4.1.1 Gross Examination 1803.4.1.2 Visual Recovery and Collection 1823.4.1.3 Recovery by Scraping 1823.4.2 Analytical Scheme 1843.4.2.1 Physical Fit 1843.4.2.2 Comparison 1853.4.2.3 Exposing of Layers 1863.4.2.4 Physical Characteristics to Note 1883.4.2.5 Further Testing 1923.5 Paint Databases 1993.5.1 The Royal Canadian Mounted Police Paint Data Query Database 2003.6 Interpretation and Report Considerations 206References 2104 Forensic Hair Microscopy 219Jason C. Beckert4.1 Introduction 2194.1.1 History 2194.2 Chemistry and Histology 2214.2.1 Basic Chemistry 2214.2.2 Basic Histology 2224.2.3 Cuticle 2234.2.4 Cortex 2244.2.5 Medulla 2254.2.6 Cell Membrane Complex 2254.2.7 Follicle 2254.3 Physiology 2254.3.1 Hair Cycle 2254.3.1.1 Timing 2264.3.1.2 Shedding 2274.3.2 Growth Rates 2284.3.3 Changes with Age 2284.3.3.1 Hair Color, Graying, and Baldness 2294.4 Collection and Isolation 2304.4.1 Questioned Samples 2304.4.1.1 Techniques 2304.4.1.2 Other Considerations 2324.4.2 Known Samples 2334.5 General Hair 2354.5.1 Types of Hair 2354.5.1.1 Human 2354.5.1.2 Animal 2364.5.2 Basic Microscopy 2374.5.2.1 Cuticle 2384.5.2.2 Cortex 2394.5.2.3 Medulla 2414.5.3 Basic Hair Identification 2414.5.4 Human Versus Animal Hair 2424.6 Human Hair Examinations 2454.6.1 Somatic Origin 2454.6.2 Ancestry 2474.6.3 Cosmetic Treatment 2494.6.4 Shaft Abnormalities 2524.6.5 Hair End Morphology 2544.6.5.1 Typical Root Morphology 2544.6.5.2 General Significance 2564.6.5.3 Suitability for DNA Testing 2564.6.5.4 Postmortem Changes 2574.6.5.5 Other Atypical Root Morphologies 2594.6.5.6 Non-root Morphologies 2594.6.6 Degradation 2624.6.6.1 Weathering 2624.6.6.2 Heat 2644.6.6.3 Biodeterioration 2654.6.6.4 Other General Changes 2684.7 Human Hair Comparisons 2684.7.1 Comparison Guidelines 2694.7.1.1 Macroscopic Observations and Stereomicroscopy 2694.7.1.2 Compound Light Microscopy 2694.7.1.3 Comparison Microscopy 2704.7.2 Conclusions and Interpretation 2724.7.2.1 Association 2724.7.2.2 Inconclusive 2744.7.2.3 Exclusion 2744.8 Transfer and Persistence 2754.9 Animal Hair 2794.9.1 Identification 2804.9.2 Cats and Dogs 2834.9.3 Textile Fur Fibers 2864.10 Specialized Techniques 2874.10.1 Examination of the Cuticular Surface 2874.10.2 Transverse Cross-sections 2894.10.3 Longitudinal Cross-sections 2914.11 Practical Considerations 2944.11.1 Training 2944.11.2 Reference Collections 2954.11.3 Examination Guidelines 2964.11.4 Documentation, Report Writing, and Testimony 2984.12 Criticisms 2994.12.1 Probability 2994.12.2 FBI Review 3004.13 Summary: The Value of Forensic Hair Microscopy 301References 3045 Fibers 322Sandra Koch and Kornelia Nehse5.1 Introduction to Forensic Fiber Analysis 3225.2 Fiber Overview 3235.2.1 Textile Production: Fiber – Yarn/Cordage – Fabric 3235.2.2 Fiber Types 3285.2.2.1 Natural Fibers 3285.2.2.2 Manufactured Fibers 3325.2.3 Fiber/Textile Coloration 3385.3 Forensic Fiber Examination Background 3395.3.1 Transfer and Persistence 3395.3.2 Collection 3425.3.2.1 Recognition, Collection, and Preservation 3425.3.2.2 Collection 3435.3.2.3 Visual Recovery: Picking 3435.3.2.4 Other Recovery Methods: Taping, Scraping, and Vacuuming 3435.3.3 Identification 3445.3.3.1 Natural Fiber Identification 3455.3.4 Comparison 3515.4 Microscopical Analysis 3525.4.1 Stereomicroscopy 3535.4.2 Brightfield Microscopy 3545.4.3 Polarized Light Microscopy 3545.4.4 Fluorescence Microscopy 3555.4.5 Comparison Microscopy 3555.4.6 Scanning Electron Microscopy 3565.5 Instrumental Analysis 3565.5.1 Microspectrophotmetry: UV-Visible 3565.5.2 Fourier Transform Infrared Spectroscopy 3575.5.3 Raman Spectroscopy 3585.5.4 Other Analytical Techniques (Non-routine) 3595.5.4.1 Thin-layer Chromatography 3595.5.4.2 Pyrolysis-Gas Chromatography Mass Spectrometry and Pyrolysis-Mass Spectrometry 3615.5.4.3 High-Performance Liquid Chromatography 3615.5.4.4 Melting Point 3615.6 Microscopic Characteristics to Note in Forensic Fiber Examinations 3615.7 Optical Properties 3615.8 Chemistry 3625.8.1 Solubility Testing 3625.9 Forensic Examination 3635.9.1 Analytical Scheme 3635.9.2 Fabric and Cordage Examinations 3635.9.2.1 Fabric Damage 3635.9.2.2 Cordage 3685.10 Interpretation and Reporting 3685.10.1 Interpretation 3685.10.2 Report Writing 3695.11 Testimony 370References 3706 Interpretation of Glass Evidence 377James Curran, Tacha Hicks, and Tatiana Trejos6.1 Introduction to Glass Examination 3776.1.1 Composition, Manufacture, and Distribution 3786.1.2 Forensic Examination Protocols 3806.1.3 Refractive Index 3806.1.4 Refractive Index Annealing 3826.1.5 Elemental Analysis of Glass 3826.1.5.1 SEM-EDS 3836.1.5.2 Micro-X-Ray Fluorescence 3836.1.5.3 ICP Methods 3836.1.5.4 LIBS 3856.1.6 Comparison of Discrimination Capabilities of the Methods of Analysis 3866.2 Introduction to the Interpretation of Glass Evidence 3876.2.1 Formulation ofWorking Propositions and Case Pre-assessment 3886.2.2 Evaluation of Results Given Source Level Propositions 3906.2.3 Evaluation of Results Given Activity Level Propositions 3916.2.4 A Note on the Use of “Contact” or Pseudo-Activity Level Propositions 3916.2.5 Evaluation of Results Given Offence Level Propositions 3926.2.6 Evaluation of Results Given Source Level Propositions 3936.2.7 The Two-Stage Approach 3946.2.7.1 Interpretation Based on RI Measurements 3946.2.7.2 Student’s t-Test 3976.2.7.3 Interpretation Based on Elemental Analysis Measurements 4016.2.7.4 Match Steps for Elemental Analysis 4026.2.7.5 Disadvantages of the Two-Stage Approach 4046.2.8 The Continuous Approach 4046.2.8.1 Interpretation Based on RI Measurements 4056.2.8.2 Interpretation Based on Elemental Analysis Measurements 4076.2.8.3 Evaluation of Results Given Activity Level Propositions 4086.2.8.4 Example 1: One Group, One Control 4096.2.9 Assigning Background and Transfer Probabilities 4106.3 Concluding Remarks 412References 4137 Interpreting Trace Evidence 421Patrick Buzzini and James M. Curran7.1 What is Evidence Interpretation? 4217.2 A Process of Uncertainties 4227.3 Factors Affecting Evidence Interpretation 4267.3.1 The Context of the Case 4267.3.2 The Questions Directed to the Forensic Scientist and Hypothesis Formulation 4277.3.3 Extent of Collected Analytical Information, Reliability, and Validity 4297.3.4 The Degree of Similarity Between Compared Sets 4317.4 Some Interpretive Issues: The Example of the Birmingham Six Bombing Case 4327.4.1 Prosecutor’s Fallacy or the Transposed Conditional 4337.4.2 Inappropriate Level of Propositions 4347.4.3 Misconception of the 99% 4347.4.4 Non-consideration of Plausible Defense Arguments 4357.5 The Bayesian Approach 4367.6 Implications of Expert Conclusions from Comparative Examinations: An Example with Fiber Evidence 4387.6.1 Conclusion 1: Factual Reporting 4397.6.2 Conclusion 2: Consistent with, Cannot Be Excluded, and Reasonable Degree of Certainty 4397.6.3 Conclusion 3: High Discriminating Procedure 4397.6.4 Conclusion 4: Rarity Assessment of the Suspected Source 4397.6.5 Conclusion 5: “Association Key” Verbal Scale 4407.6.6 Conclusion 6: Likelihood Ratio Verbal Scale 4427.7 Conclusion 446Acknowledgments 447References 447Index 455

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