Handbook of Trace Evidence Analysis E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 1160

Veröffentlichungsjahr: 2020

Beschreibung

Covers new trace evidence techniques and expanding areas of analysis, along with key theory and applications

Developed around the need for updated information in the disciplines of trace evidence the Handbook of Trace Evidence Analysis focuses on the increasing awareness and need for validation, modern methods for addressing and controlling contamination, the shift towards incorporating statistical analyses into the interpretation phase and cutting edge research into new forensic science methods and their application. 

Beginning with an overview of the topic and discussing the important role that information derived from trace materials can provide during investigations, the book then presents chapters on key techniques. The first being the critical nature of microscopy, and the methods employed for the recognition, collection, and preservation of trace evidence. Subsequent chapters review the core disciplines of trace evidence examination: paints and polymers, hairs, fibers and textiles and glass. Each chapter contains in-depth discussions on the origin of the materials involved, including any natural or synthetic processes involved in their production, the nuances involved in their detection, and the methods of analysis that are used to extract valuable information from samples. In addition, suggested workflows in method and testing selections, as well as addressing specific scientific challenges as well as the limitations of knowledge on the transfer, persistence and background abundance of trace materials are discussed. The book ends by examining the interpretation of trace evidence findings from a historical perspective and examining the methods that are currently being developed.

• Provides an in-depth introduction to the general area of trace evidence and discusses current and new techniques
• Consolidates trace evidence and materials categories of testing into one reference series
• Offers a detailed focus on technical approaches and guidelines to trace evidence
• Includes analytical schemes/workflows and valuable guides for the interpretation of data and results

The Handbook of Trace Evidence will appeal to forensic science academics, students, and practitioners in the trace evidence and materials science disciplines, as well as DNA analysts, toxicologists, forensic anthropologists, crime laboratory managers, criminal justice students and practitioners, and legal professionals. It would also be a valuable resource for every crime laboratory reference library.

Leseprobe

Table of Contents

Cover

List of Contributors

Preface

1 Trace Evidence Recognition, Collection, and Preservation

1.1 Introduction

1.2 Theories of Transfer and Persistence

1.3 Proper Evidence Handling Practices

1.4 Recognition, Collection, and Preservation of Trace Evidence at the Crime Scene

1.5 Recognition, Collection, and Preservation of Trace Evidence in the Laboratory

1.6 Summary

Acknowledgments

References

Further Reading

2 Polarized Light Microscopy for the Trace Evidence Examiner

2.1 Introduction

2.2 The Nature of Light

2.3 Light Microscopy

2.4 Introduction to Crystallography

2.5 Introduction to Optical Crystallography

2.6 Measurement of Optical Properties

2.7 Identification of an Unknown Using Optical Properties

References

3 Paints and Polymers

3.1 Introduction to the Paint and Polymer Discipline

3.2 Overview of Polymer Chemistry

3.3 Overview of Coatings

3.4 Forensic Examination

3.5 Paint Databases

3.6 Interpretation and Report Considerations

References

4 Forensic Hair Microscopy

4.1 Introduction

4.2 Chemistry and Histology

4.3 Physiology

4.4 Collection and Isolation

4.5 General Hair

4.6 Human Hair Examinations

4.7 Human Hair Comparisons

4.8 Transfer and Persistence

4.9 Animal Hair

4.10 Specialized Techniques

4.11 Practical Considerations

4.12 Criticisms

4.13 Summary: The Value of Forensic Hair Microscopy

References

5 Fibers

5.1 Introduction to Forensic Fiber Analysis

5.2 Fiber Overview

5.3 Forensic Fiber Examination Background

5.4 Microscopical Analysis

5.5 Instrumental Analysis

5.6 Microscopic Characteristics to Note in Forensic Fiber Examinations

5.7 Optical Properties

5.8 Chemistry

5.9 Forensic Examination

5.10 Interpretation and Reporting

5.11 Testimony

References

5.A Appendix

6 Interpretation of Glass Evidence

6.1 Introduction to Glass Examination

6.2 Introduction to the Interpretation of Glass Evidence

6.3 Concluding Remarks

References

7 Interpreting Trace Evidence

7.1 What is Evidence Interpretation?

7.2 A Process of Uncertainties

7.3 Factors Affecting Evidence Interpretation

7.4 Some Interpretive Issues: The Example of the Birmingham Six Bombing Case

7.5 The Bayesian Approach

7.6 Implications of Expert Conclusions from Comparative Examinations: An Example with Fiber Evidence

7.7 Conclusion

Acknowledgments

References

Index

End User License Agreement

List of Tables

Chapter 1

Table 1.1 Proper PPE and reasons for using it.

Chapter 2

Table 2.1 A list of common isotropic substances and their refractive index va...

Table 2.2 Symmetry elements and their symbols.

Table 2.3 Several habit terms that are commonly used by mineralogists, along ...

Table 2.4 Retardation values and corresponding retardation colors.

Table 2.5 Extinction types on principal sections for different crystal system...

Chapter 3

Table 3.1 Associated binder types and crosslinkers with their respective end ...

Table 3.2 Common extender pigments used in coatings

Table 3.3 Automotive coating trends

Table 3.4 Microchemical reactions helpful for paint classification

Table 3.5 Associations of evidence and examples

Chapter 4

Table 4.1 Human head hair growth rates (in μm/day) for three different ancest...

Table 4.2 Summary of pubic hairs recovered from combings after sexual interco...

Table 4.3 Summary of laundered hair study

Table 4.4 Summary of hair transfer to clothing in sexual assaults

Table 4.5 Summary of hairs recovered from victim's hands/fingernail scrapings

Chapter 5

Table 5.1 Characteristics useful for differentiating among natural fibers

Table 5.2 Fiber properties useful to differentiate among manufactured fiber t...

Table 5.3 Melting point determination and thermal decomposition

Table 5.4 Example of a table used to document the physical characteristics, o...

Chapter 6

Table 6.1 Refractive index measurements from an example case.

Table 6.2 Summary statistics from an example case.

Table 6.3 Refractive index measurements from an example case.

Table 6.4 Match results from an example case.

Chapter 7

Table 7.1 Association key verbal scale. Source: Courtesy of Bommarito 2009.

Table 7.2 Symmetric spectrum of conclusions for hair comparisons Source: Repr...

Table 7.3 Example of likelihood ratio scale.

List of Illustrations

Chapter 1

Figure 1.1 An example of a two‐way transfer. (a) An article of clothing bein...

Figure 1.2 A sheet of plate glass being broken by a hammer. The broken glass...

Figure 1.3 A muddy shoe (a) and a muddy impression (b).

Figure 1.4 An analyst wearing various items of PPE.

Figure 1.5 Fibers on an article of clothing. A shirt in normal room light (a...

Figure 1.6 Some packaging materials for the collection of trace evidence. Fr...

Figure 1.7 The making of a paper fold, also known as a druggist fold. The in...

Figure 1.8 Tape lifting a car seat with 2‐in. wide clear tape.

Figure 1.9 An example of trace evidence hinge lifters.

Figure 1.10 An example of a trace evidence vacuum cleaner with a single‐use ...

Figure 1.11 Vacuuming for trace evidence using a hand‐held vacuum with a reu...

Figure 1.12 An electrostatic lifting device.

Figure 1.13 The dusty impression resulting from the electrostatic lifting de...

Figure 1.14 Using a stereomicroscope on a benchtop boom.

Figure 1.15 A stereomicroscope on a rolling floor‐stand boom.

Figure 1.16 Picking trace evidence using tweezers.

Figure 1.17 Cleaning the tweezers with ethanol.

Figure 1.18 The scraping technique in which a spatula is used to scrape trac...

Figure 1.19 The shaking technique in which the article is shaken to dislodge...

Figure 1.20 Funneling trace evidence into a paper fold after shaking and scr...

Figure 1.21 The tape‐lifting technique in which clear packing tape is presse...

Figures 1.22 (a) Tape lifting of debris which had been previously dislodged ...

Chapter 2

Figure 2.1 A wave of light showing its wavelength (

λ

), amplitude (

A

), p...

Figure 2.2 Unpolarized light composed of light waves vibrating in all possib...

Figure 2.3 Plane polarized light. As opposed to Figure 2.2, the light waves ...

Figure 2.4 Light partially reflecting off a glass surface. The angles of inc...

Figure 2.5 The top image illustrates regular reflection off a smooth surface...

Figure 2.6 In addition to reflection, a portion of the light incident on a p...

Figure 2.7 A bundle of parallel light rays with a line connecting portions o...

Figure 2.8 Figure 2.6 shown again with the incident light redrawn as a paral...

Figure 2.9 A pair of wheels connected by an axle traveling from concrete (gr...

Figure 2.10 A typical dispersion curve, illustrating how refractive index ch...

Figure 2.11 A modern polarized light microscope with most of its components ...

Figure 2.12 Diagram A illustrates some important terms related to image form...

Figure 2.13 The top portion of the figure illustrates how the visual angle c...

Figure 2.14 Two images of the same diatom, taken at the same magnification b...

Figure 2.15 Three objectives with different numerical apertures. Lenses with...

Figure 2.16 Diffraction of light waves passing through a single slit (left) ...

Figure 2.17 The top left diagram illustrates the light path for light rays p...

Figure 2.18 The upper images illustrate a specimen consisting of a series of...

Figure 2.19 A series of slits illuminated by unidirectional axial illuminati...

Figure 2.20 A series of slits illuminated by unidirectional oblique illumina...

Figure 2.21 Multidirectional oblique illumination is achieved by illuminatin...

Figure 2.22 A properly focused substage condenser (left) illuminating the sa...

Figure 2.23 The impact of the size of the condenser aperture opening on the ...

Figure 2.24 The image on the left shows a red nylon fiber with the field dia...

Figure 2.25 Two photomicrographs of a dark polyester wig fiber taken under s...

Figure 2.26 The line designated m indicates the presence of a mirror plane i...

Figure 2.27 The square in the center of the crystal indicates the presence o...

Figure 2.28 The hexagon in the center of the crystal indicates the presence ...

Figure 2.29 The dark eye shape in the center of the crystal indicates the pr...

Figure 2.30 The triangle in the center of the crystal indicates the presence...

Figure 2.31 The circle enclosing a dot in the center of the crystal indicate...

Figure 2.32 The red symbol above the crystal indicates the presence of fourf...

Figure 2.33 The cubic crystal system is characterized by the presence of fou...

Figure 2.34 Three cubic crystal forms shown in perspective (top) and in seve...

Figure 2.35 The tetragonal crystal system is characterized by the presence o...

Figure 2.36 Three tetragonal crystal forms shown in perspective (top) and in...

Figure 2.37 The hexagonal crystal system is characterized by the presence of...

Figure 2.38 Three hexagonal crystal forms shown in perspective (top) and in ...

Figure 2.39 Two orthorhombic crystal forms shown in perspective (top) and in...

Figure 2.40 Two monoclinic crystal forms shown in perspective (top) and in t...

Figure 2.41 Two triclinic crystal forms shown in perspective (top) and in se...

Figure 2.42 Examples of crystals with well‐developed forms (euhedral, top), ...

Figure 2.43 The intercepts of the anhydrite unit face (

a

,

b

,

c

) are shown al...

Figure 2.44 The intercepts of the anhydrite unit face (

a

,

b

,

c

) are shown al...

Figure 2.45 In this example, the presence of a center of symmetry (

i

) and Fa...

Figure 2.46 One important property useful for the identification of mineral ...

Figure 2.47 The crystal structure of sodium chloride (table salt) shown in p...

Figure 2.48 The indicatrix of an isotropic substance with refractive index =...

Figure 2.49 Sodium chloride indicatrices for different wavelengths of light ...

Figure 2.50 A cubic crystal's indicatrix illuminated from below with unpolar...

Figure 2.51 A cubic crystal's indicatrix illuminated from below with both un...

Figure 2.52 A cubic crystal illuminated from below with unpolarized light, o...

Figure 2.53 A cubic crystal illuminated from below with unpolarized light, o...

Figure 2.54 A calcite crystal exhibiting double refraction. The drawing of t...

Figure 2.55 The crystal structure of calcium carbonate (calcite) shown in pe...

Figure 2.56 A wave of light traveling through an anisotropic substance as an...

Figure 2.57 The light path for both the O ray (blue) and the E ray (green) t...

Figure 2.58 The indicatrix of a uniaxial substance with refractive indices h...

Figure 2.59 The three types of sections that occur in a uniaxial indicatrix....

Figure 2.60 A hexagonal (uniaxial) calcite crystal illuminated from below wi...

Figure 2.61 A hexagonal (uniaxial) calcite crystal illuminated from below wi...

Figure 2.62 A hexagonal (uniaxial) calcite crystal illuminated from below wi...

Figure 2.63 Examples of indicatrices for uniaxial positive (left) and negati...

Figure 2.64 The crystal structure of anhydrite (calcium sulfate) looking dow...

Figure 2.65 The indicatrix of a biaxial substance with refractive indices ha...

Figure 2.66 The three principal sections in a biaxial indicatrix, namely the...

Figure 2.67 A biaxial indicatrix shown with its two circular sections indica...

Figure 2.68 A semi‐random section in a biaxial indicatrix that includes one ...

Figure 2.69 A random section in a biaxial indicatrix that does not include a...

Figure 2.70 An orthorhombic (biaxial) anhydrite crystal illuminated from bel...

Figure 2.71 An orthorhombic (biaxial) anhydrite crystal illuminated from bel...

Figure 2.72 An orthorhombic (biaxial) anhydrite crystal illuminated from bel...

Figure 2.73 Indicatrices of biaxial positive (left) and negative (right) sub...

Figure 2.74 Several biaxial indicatrices are shown, each one having the same...

Figure 2.75 The optical orientation of anhydrite, for which

β

is parall...

Figure 2.76 The optical orientation of gypsum, for which

β

is parallel ...

Figure 2.77 A particle having a refractive index relatively far from that of...

Figure 2.78 A calcite crystal exhibiting high contrast against its mounting ...

Figure 2.79 A particle having a refractive index relatively close to that of...

Figure 2.80 A calcite crystal exhibiting low contrast against its mounting m...

Figure 2.81 A particle having a refractive index that matches that of the mo...

Figure 2.82 In practice, a particle will only have a refractive index that m...

Figure 2.83 Photomicrograph of barium nitrate particles with pale blue and y...

Figure 2.84 A particle having a refractive index greater than that of the mo...

Figure 2.85 A particle shown at best focus (left), and again after raising t...

Figure 2.86 A particle having a refractive index less than that of the mount...

Figure 2.87 A particle shown at best focus (left), and again after raising t...

Figure 2.88 An example of a certified refractive index liquid from Cargille ...

Figure 2.89 This graph is an example of a Hartmann net, which is used to plo...

Figure 2.90 The standard orientation of the polarizer's principal vibration ...

Figure 2.91 A calcite rhomb oriented such that its

ω

vibration directio...

Figure 2.92 A calcite rhomb oriented such that its

ε

′ vibration directi...

Figure 2.93 A calcite rhomb oriented such that the principal vibration direc...

Figure 2.94 A recrystallized potassium dihydrogen phosphate crystal (tetrago...

Figure 2.95 Possible refractive indices presented by calcite grains in vario...

Figure 2.96 A tourmaline crystal exhibiting strong pleochroism, with a pleoc...

Figure 2.97 Possible refractive indices presented by anhydrite crystals in v...

Figure 2.98 A hornblende grain exhibiting strong pleochroism. The polarizer ...

Figure 2.99 This diagram depicts a ray of plane polarized light entering an ...

Figure 2.100 A calcite crystal shown with its vibration directions at a 45° ...

Figure 2.101 An anisotropic crystal (olivine) shown in between crossed polar...

Figure 2.102 The variation in intensity of monochromatic light as a function...

Figure 2.103 The top image shows two parent waves (blue and red) vibrating i...

Figure 2.104 If the red wave from Figure 2.103 were shifted by ½

λ

, the ...

Figure 2.105 The behavior of plane polarized light passing through an anisot...

Figure 2.106 The behavior of plane polarized light passing through an anisot...

Figure 2.107 The individual wavelengths of light each exhibit intensity maxi...

Figure 2.108 The Michel‐Lévy chart plots three different variables, namely b...

Figure 2.109 Due to its high dispersion, the retardation colors shown by RDX...

Figure 2.110 A round fiber shown in between crossed polars. The pattern of r...

Figure 2.111 A trilobal nylon fiber shown in cross‐section (left), and in be...

Figure 2.112 A dog bone‐shaped acrylic fiber shown in between crossed polars...

Figure 2.113 A triangular polypropylene fiber shown in cross‐section (left),...

Figure 2.114 A quartz grain (top left) and a tremolite grain (top right) exh...

Figure 2.115 An olivine grain (left) and a carbonate grain (right) exhibitin...

Figure 2.116 Two calcite grains exhibiting high‐order white retardation colo...

Figure 2.117 When the vibration direction of the incident plane polarized li...

Figure 2.118 A sodium nitrate crystal exhibiting symmetrical extinction. The...

Figure 2.119 A 2,4,6‐trinitrotoluene (TNT) crystal exhibiting parallel extin...

Figure 2.120 A 2,4‐dinitrotoluene (DNT) crystal exhibiting oblique extinctio...

Figure 2.121 Two crystals with their vibration directions indicated by the r...

Figure 2.122 An extinction angle is measured by first aligning the crystal f...

Figure 2.123 A diagram depicting a polycrystalline particle in two different...

Figure 2.124 A photomicrograph of a polycrystalline grain from a fine‐graine...

Figure 2.125 A diagram of a grain composed of two crystal twins. The behavio...

Figure 2.126 Photomicrographs of (a) microcline twins and (b) plagioclase tw...

Figure 2.127 A diagram depicting a crystal exhibiting dispersed extinction. ...

Figure 2.128 Photomicrographs of an RDX crystal shown at a position of brigh...

Figure 2.129 A diagram depicting the orientation of cellulose polymer chains...

Figure 2.130 Photomicrographs of a cotton fiber shown in two positions in be...

Figure 2.131 A diagram depicting the orientation of the carbohydrate polymer...

Figure 2.132 A potato starch grain shown in between crossed polars.

Figure 2.133 This diagram shows two identical crystals that are both in the ...

Figure 2.134 This diagram shows the same crystals that are depicted in Figur...

Figure 2.135 The appearance of a celestine crystal with a positive sign of e...

Figure 2.136 The appearance of an apatite crystal with a negative sign of el...

Figure 2.137 An acetate rayon fiber shown in between crossed polars (left) a...

Figure 2.138 An acrylic fiber shown in between crossed polars (left) and aga...

Figure 2.139 For fibers with higher retardation colors, such as the nylon fi...

Figure 2.140 A depiction of the indicatrix sections that are encountered by ...

Figure 2.141 The rays indicated in Figure 2.140 are shown after they have pa...

Figure 2.142 The vibration directions for several rays that have traveled th...

Figure 2.143 A centered uniaxial interference figure. The melatope (emergenc...

Figure 2.144 A centered uniaxial interference figure shown with the compensa...

Figure 2.145 The appearance of centered uniaxial interference figures for a ...

Figure 2.146 A slightly off center uniaxial interference figure with its opt...

Figure 2.147 An expanded view of the uniaxial interference figure in Figure ...

Figure 2.148 As the stage is rotated, the appearance of the interference fig...

Figure 2.149 If a compensator is inserted into the microscope, the upper rig...

Figure 2.150 When the melatope (center of the cross) is due South (or due No...

Figure 2.151 An off center uniaxial interference figure with its optic axis ...

Figure 2.152 An expanded view of the uniaxial interference figure in Figure ...

Figure 2.153 As the stage is rotated, the appearance of the interference fig...

Figure 2.154 The interference figure shown in Figure 2.151, rotated into a p...

Figure 2.155 The interference figure shown in Figure 2.151 oriented such tha...

Figure 2.156 The interference figure of a low birefringent uniaxial substanc...

Figure 2.157 The interference figure of a highly birefringent uniaxial subst...

Figure 2.158 An off‐center interference figure with a third‐order red retard...

Figure 2.159 A depiction of the indicatrix sections that are encountered by ...

Figure 2.160 The rays indicated in Figure 2.159 are shown after they have pa...

Figure 2.161 A centered acute bisectrix (Bxa) biaxial interference figure. T...

Figure 2.162 A centered Bxa interference figure with the trace of the optic ...

Figure 2.163 The appearance of centered Bxa interference figures for a cryst...

Figure 2.164 The appearance of centered Bxa interference figures for a cryst...

Figure 2.165 Bxa interference figures for crystals with different optic axia...

Figure 2.166 The Bxa interference figure of a biaxial substance with low bir...

Figure 2.167 The Bxa interference figure of a biaxial substance with high bi...

Figure 2.168 Nearly centered optic axis figure for a biaxial substance (TNT)...

Figure 2.169 The appearance of centered optic axis interference figures for ...

Figure 2.170 Several off‐center Bxa and optic axis biaxial interference figu...

Figure 2.171 A centered Bxo biaxial interference figure.

Figure 2.172 A nearly centered optic axis interference figure obtained for a...

Figure 2.173 A Bloss detent spindle stage.

Chapter 3

Figure 3.1 Paint chip with bottommost surface visible with areas appearing s...

Figure 3.2 Cross‐section of tri‐coat paint sequence: clearcoat, clearcoat wi...

Figure 3.3 Cross‐section in transmitted light of quad‐coat paint sequence: c...

Figure 3.4 Cross‐section of OEM repair with three basecoat/clearcoat topcoat...

Figure 3.5 Example of aftermarket automotive refinish paint layers above OEM...

Figure 3.6 Image of a paint chip viewing the bottom side of the chip such th...

Figure 3.7 Note the smearing of the architectural paint layers within the de...

Figure 3.8 Following a homicide, one suspect stated that they, along with a ...

Figure 3.9 Paint from a safe. Visually very distinctive due to hills and val...

Figure 3.10 Side view of a paint chip, magnification ∼55×. Note the thick ta...

Figure 3.11 Road paint (magnification ∼12×), notice the distinctive glass ba...

Figure 3.12 Two trash‐sized plastic bags side‐by‐side over a light box. Bag ...

Figure 3.13 Paint is often transferred to pedestrian clothing in hit‐and‐run...

Figure 3.14 The shirt is suspended above a paper covered surface. The spatul...

Figure 3.15 Analytical scheme for forensic paint analysis. Optional, less co...

Figure 3.16 Examples of physical reconstructions. Fits were confirmed with s...

Figure 3.17 Paint chip (top) and the manual methods of exposing layers: (a) ...

Figure 3.18 Example of layer designators on a typical four‐layer OEM automot...

Figure 3.19 PDQ reference guide, an aid to coding binders and pigments in au...

Figure 3.20 A PDQ record capturing source information, layer sequence, chemi...

Figure 3.21 Parameters of a layer system query search.

Figure 3.22 The PDQ Hit List is a list of known vehicles that are similar in...

Chapter 4

Figure 4.1 Human head hair exhibiting a distinct cuticle (arrows), cortex, a...

Figure 4.2 Human head hair with the free ends of the cuticular scales pointi...

Figure 4.3 Human head hair exhibiting a natural progression from a proximal ...

Figure 4.4 Example of a bulge on a human hair caused by excessive force appl...

Figure 4.5 Examples of guard hairs (top) and fur hairs (bottom) from a racco...

Figure 4.6 Guard hairs from an American mink (

Neovison vison

) exhibiting dis...

Figure 4.7 Example of a human head hair exhibiting a distinctly colored cuti...

Figure 4.8 SEM photomicrograph of a human hair from a wig, lacking a cuticle...

Figure 4.9 Frayed end of a human head hair with individual cortical cells vi...

Figure 4.10 Parallel interference colors in a straight human head hair (moun...

Figure 4.11 Distorted interference colors in a slightly twisted human head h...

Figure 4.12 Cortical fusi, a few of which are marked with arrows, in the sha...

Figure 4.13 Distinct pigment granules, a few of which are marked with arrows...

Figure 4.14 Example of an ovoid body, marked with an arrow, in the shaft of ...

Figure 4.15 Continuous medulla in the shaft of a human head hair, mounted in...

Figure 4.16 Examples of partially (left) and completely (right) fluid‐filled...

Figure 4.17 Moose (

Alces alces

) hair exhibiting undulations (left) and a sho...

Figure 4.18 Nitrogen gas bubbles forming on a human head hair upon exposure ...

Figure 4.19 Transverse cross‐sections of a brown human head hair exhibiting ...

Figure 4.20 Cleared longitudinal cross‐section of a hair from a pet rat (

Rat

...

Figure 4.21 Large, elongated root of a brown bear (

Ursus arctos

) mounted in ...

Figure 4.22 Buckle in the shaft of a human pubic hair (mounted in xylene and...

Figure 4.23 Telogen root from a naturally shed human pubic hair (mounted in ...

Figure 4.24 Elaborate cross‐sectional shape in a human beard hair (mounted i...

Figure 4.25 Example of a head hair from a person of East Asian ancestry (mou...

Figure 4.26 Example of a head hair from a person of European ancestry (mount...

Figure 4.27 Example of a head hair from a person of sub‐Saharan African ance...

Figure 4.28 Dye‐line in a human head hair in which the proximal, light brown...

Figure 4.29 Bleach‐line in a human head hair in which the proximal, brown pi...

Figure 4.30 Close‐up view of the cortical texture in the shaft of a heavily ...

Figure 4.31 Louse egg, with a louse inside, adhering to the hair shaft from ...

Figure 4.32 Human head hair with an anagen root (mounted in xylene and viewe...

Figure 4.33 Human head hair with a telogen root (mounted in xylene and viewe...

Figure 4.34 Human head hair with a catagen root (mounted in xylene and viewe...

Figure 4.35 Post‐mortem root band in the shaft of a human head hair, mounted...

Figure 4.36 Human head hair with a pointed proximal end indicative of post‐m...

Figure 4.37 Human head hair with a naturally tapering tip (mounted in xylene...

Figure 4.38 Human head hair with a scissor cut tip (mounted in xylene and vi...

Figure 4.39 Human beard hair with two razor cut ends (mounted in xylene and ...

Figure 4.40 Human head hair with a clipper cut tip (mounted in xylene and vi...

Figure 4.41 Human head hair with a rounded tip (mounted in xylene and viewed...

Figure 4.42 Human head hair with a broken proximal end (mounted in xylene an...

Figure 4.43 Human head hair with a crushed proximal end (mounted in xylene a...

Figure 4.44 Human head hair with a split tip (mounted in xylene and viewed u...

Figure 4.45 Human head hair with a burned proximal end (mounted in xylene an...

Figure 4.46 Scale cast of the shaft of a human head hair with jagged cuticul...

Figure 4.47 Human head hair with lifted cuticular scales (mounted in xylene ...

Figure 4.48 SEM micrograph of a human head hair with lifted cuticular scales...

Figure 4.49 Human hair shaft with bulges resulting from thermal degradation ...

Figure 4.50 Cow (

Bos taurus

) hair shaft exhibiting insect damage, mounted in...

Figure 4.51 Hastiseta “hair” from the larva of a dermestid beetle (left) wit...

Figure 4.52 Examples of fungal hyphae on the shafts of rabbit hairs (mounted...

Figure 4.53 Human hair shaft exhibiting a looped cuticle (mounted in xylene ...

Figure 4.54 Human eyebrow hair exhibiting a double medulla (mounted in xylen...

Figure 4.55 Photomicrograph taken using a comparison microscope of two head ...

Figure 4.56 Cleared longitudinal cross‐section of a dyed rabbit hair (mounte...

Figure 4.57 Guard hairs from a coyote (

Canis latrans

) exhibiting four distin...

Figure 4.58 Pig (

Sus scrofa

) hair exhibiting a split tip (mounted in xylene ...

Figure 4.59 “Wine‐glass” shaped root from a white‐tailed deer (

Odocoileus vi

...

Figure 4.60 SEM photomicrograph of the shaft of a guard hair from a short‐ta...

Figure 4.61 Straight (left), fringed (middle), and scalloped (right) medulla...

Figure 4.62 Transverse cross‐sections of guard hairs from an Eastern cottont...

Figure 4.63 Cleared longitudinal cross‐sections of a domestic cat (left) and...

Figure 4.64 Scale cast of the shaft of a guard hair from an American mink (

N

...

Figure 4.65 Cross‐section of wig hairs made using a Schwarz microtome (left)...

Figure 4.66 Whole mount of a guard hair from a white‐tailed deer (

Odocoileus

...

Figure 4.67 Example of serendipitous clearing in the shaft of a guard hair o...

Figure 4.68 Partial clearing of a guard hair from a short‐tailed shrew (

Blar

...

Figure 4.69 Human hair shaft with a particle of glitter (circled) adhering t...

Figure 4.70 Isotropic residue on the surface of a human head hair (mounted i...

Chapter 5

Figure 5.1 Yarn direction of twist: S and Z twists.

Figure 5.2 Cordage (a) counting plies in braid, (b) counting plies by labeli...

Figure 5.3 (a) Plain weave and (b) patterned weave.

Figure 5.4 (a) Twill weave and (b) satin weave.

Figure 5.5 Knit fabric.

Figure 5.6 Non‐woven material: fibers melt bonded together to create textile...

Figure 5.7 Carpet loops.

Figure 5.8 Cotton seed boll.

Figure 5.9 Hemp fiber ultimates and technical fibers.

Figure 5.10 Seed fibers: (a) cotton and (b) Kapok.

Figure 5.10 Stem fibers: flax, jute, hemp, and ramie technical fibers.

Figure 5.12 Wool fiber with variable diameter and dye uptake.

Figure 5.13 Silk: (a) cocoon, (b) mulberry silk fiber (double strand), and (...

Figure 5.14 Spinning production methods.

Figure 5.15 Diagram of fiber production from solution through spinneret to f...

Figure 5.16 Viscose rayon fibers with bluish white and yellow‐orange interfe...

Figure 5.17 Acrylic fiber.

Figure 5.18 Olefin fiber.

Figure 5.19 Nylon trilobal carpet‐type fiber.

Figure 5.20 IR spectra of nylon 6 and 6.6 with the fingerprint region highli...

Figure 5.21 Polyester fiber.

Figure 5.22 (a) IR spectra of polyesters PET (red), PBT (yellow) and PTT (bl...

Figure 5.23 Kevlar fiber.

Figure 5.24 Cotton fibers.

Figure 5.25 Kapok fiber under (a) transmitted light and (b) between crossed ...

Figure 5.26 Flax.

Figure 5.27 Hemp.

Figure 5.28 Jute.

Figure 5.29 Ramie.

Figure 5.30 Drying twist test: as the above fiber dries, the tip starts to r...

Figure 5.31 Sisal at 200×: (a) transmitted light PLM microscope, (b) crossed...

Figure 5.32 Leaf fibers: abaca (manilla) fiber with crystalline stegmata and...

Figure 5.33 Color change in abaca and sisal after Billinghame's test.

Figure 5.34 Fruit fiber: coir.

Figure 5.35 Animal hairs as textile fibers (transmitted light microscopy): (...

Figure 5.36 SEM images: merino wool, llama, alpaca, and angora rabbit.

Figure 5.37 Trilobal fiber morphology (a) longitudinal view and (b) in cross...

Figure 5.38 Fabric damage cut/tear differentiation.

Figure 5.39 Fabric damage: a) knife stabs through folded paper shows directi...

Figure 5.40 Fabric damage: if a decorative pattern makes it difficult to obs...

Figure 5.41 Fabric damage: (a) button torn from fabric leaving hole and (b) ...

Figure 5.42 Fabric examination: “physical fit”. The long and short yarns fro...

Figure 5.A1

Chapter 6

Figure 6.1 Example of methods for the recovery of glass shards using (a) and...

Figure 6.2 Scheme of a typical analytical protocol for the forensic examinat...

Figure 6.3 Scheme of (a) a typical SEM‐EDS and (b) a μ‐XRF system and respec...

Figure 6.4 Scheme of a typical LIBS and laser ablation system attached to an...

Figure 6.5 Using the range test to determine matching fragments. The five fr...

Figure 6.6 Using the

3

σ

test to determine matching fragments. The three...

Figure 6.7 Using the two‐sample

t

‐test to determine matching fragments. In t...

Chapter 7

Figure 7.1 Graphs for three long run repetitions trials (

N

 = 1000) for the c...

Figure 7.2 Table summarizing the fibers from Wayne Williams's property that ...

Guide

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Handbook of Trace Evidence Analysis

Edited by

Vincent J. Desiderio

US Postal Inspection ServiceUSA

Chris E. Taylor

US Army Criminal Investigation LaboratoryUSA

Niamh Nic Daéid

University of DundeeUK

This edition first published 2021

© 2021 John Wiley & Sons Ltd

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.

The right of Vincent J. Desiderio, Chris E. Taylor, and Niamh Nic Daéid to be identified as the authors of the editorial material in this work has been asserted in accordance with law.

Registered Offices

John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA

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For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.

Wiley also publishes its books in a variety of electronic formats and by print‐on‐demand. Some content that appears in standard print versions of this book may not be available in other formats.

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In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of experimental reagents, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each chemical, piece of equipment, reagent, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. While the publisher and authors have used their best efforts in preparing this work, they make no representations or warranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives, written sales materials or promotional statements for this work. The fact that an organization, website, or product is referred to in this work as a citation and/or potential source of further information does not mean that the publisher and authors endorse the information or services the organization, website, or product may provide or recommendations it may make. This work is sold with the understanding that the publisher is not engaged in rendering professional services. The advice and strategies contained herein may not be suitable for your situation. You should consult with a specialist where appropriate. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this work was written and when it is read. Neither the publisher nor authors shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages.

Library of Congress Cataloging‐in‐Publication Data

Names: Desiderio, Vincent Joseph, Jr., editor. | Taylor, Chris Edward,

  editor. | Nic Daéid, Niamh, editor.

Title: Handbook of trace evidence analysis / edited by Vincent Joseph

  Desiderio Jr., Chris Edward Taylor, Niamh Nic Daéid.

Description: First edition. | Hoboken, NJ : Wiley, [2021] | Includes

  bibliographical references and index.

Identifiers: LCCN 2019058272 (print) | LCCN 2019058273 (ebook) | ISBN

  9781118962114 (hardback) | ISBN 9781118962107 (adobe pdf) | ISBN

  9781118962091 (epub)

Subjects: LCSH: Trace evidence. | Evidence preservation. | Forensic

  sciences. | Evidence, Criminal.

Classification: LCC HV8073.5 .H35 2020 (print) | LCC HV8073.5 (ebook) |

  DDC 363.25/62--dc23

LC record available at https://lccn.loc.gov/2019058272

LC ebook record available at https://lccn.loc.gov/2019058273

Cover Design: Wiley

Cover Images: Human head Courtesy of Sandy Koch, Aftermarket automotive Courtesy of Robyn Weimer, A triangular polypropylene Courtesy of Andy Bowen, An anisotropic crystal Courtesy of Andy Bowen

Vincent “Vinny” Desiderio: Thank you to my wife Sandi and my two boys, Eric and Ryan, for their unyielding support with everything I have ever or will ever accomplish.

Chris E. Taylor: Thank you to my wife, Patricia Caldwell, for her support in my life and professional endeavors. In remembrance of Irving and Joanne Taylor.

Niamh Nic Daéid: Thank you to my wonderful girls, Gill, Emily, Molly, and Smudge, for the constant laughs and the joy that you bring.

To all trace evidence examiners and trace evidence friends that have supported and continue to support the many disciplines of trace evidence and its value to forensic science, the American Society of Trace Evidence Examiners, and the authors that have contributed their time and knowledge to the creation of this book.

Acknowledgments from chapter authors can be found at the end of each chapter.

List of Contributors

Jason C. Beckert

Microtrace LLC

Elgin, IL, USA

Andrew M. Bowen

Physical Sciences Unit

United States Postal Inspection Service

Dulles, VA, USA

Patrick Buzzini

Department of Forensic Science

Sam Houston State University

Houston, TX, USA

Brandi L. Clark

Trace Evidence Section

Westchester County Forensic Science Laboratory

Valhalla, NY, USA

James M. Curran

Department of Statistics

The University of Auckland

Auckland, New Zealand

Tacha Hicks

Faculty of Law

Criminal Justice and Public Administration

School of Criminal Justice and Fondation pour la formation continue UNIL‐EPFL

University of Lausanne

Lausanne, Switzerland

Tamara Hodgins

Royal Canadian Mounted Police National Forensic Laboratory Service

Edmonton, AB, Canada

Sandra Koch

McCrone Associates

Westmont, IL, USA

Kornelia Nehse

Textiles and Micromorphology Department

Forensic Science Institute (LKA KTI)

Berlin, Germany

Daniel S. Rothenberg

Trace Evidence Section

Westchester County Forensic Science Laboratory

Valhalla, NY, USA

Ted R. Schwartz

Trace Evidence Section

Westchester County Forensic Science Laboratory

Valhalla, NY, USA

Tatiana Trejos

Department of Forensic and Investigative Science

West Virginia University

Morgantown, VA, USA

Robyn B. Weimer

Trace Evidence Section

Virginia Department of Forensic Science

Richmond, VA, USA

Diana M. Wright

Chemistry Unit, Federal Bureau of Investigation Laboratory

Quantico, VA, USA

Preface

The use and application of trace evidence within the forensic sciences is an important component of criminal investigations. Trace evidence can be helpful when attempting to determine if associations exist between suspects, victims, crime scenes, and/or specific objects that may have been involved in the commission of a crime. In addition, when used in the associative context, this type of evidence can also provide a great deal of investigative information. In this latter context, trace evidence can be used to support or to refute the narratives of witnesses, victims, and suspects, to reconstruct events that may have occurred, and to develop potential leads with respect to specific environments from which objects or individuals may have come or traveled to. Notwithstanding this, trace evidence has continued to see a decrease in its use by forensic science service providers across the United States as well as internationally and it is in part the consequent loss of experience and knowledge that this book aims to address.

The idea of this handbook started with a discussion between Vinny and Chris at an American Academy of Forensic Science (AAFS) meeting several years ago. Vinny and Chris were the first and second presidents, respectively, of the recently created American Society of Trace Evidence Examiners (ASTEE). Both had the passion to continue the path to bolster trace evidence resources to the forensic science community. Besides having a society in the ASTEE to bring practitioners together and support information sharing, training, and social interaction, it was believed that to continue the education and development of the future of trace evidence and its practitioners a reference text could be offered.

The AAFS meetings often allow attendees to see and catch up with colleagues and friends, and during the meeting Chris and Vinney also met up with Niamh Nic Daéid, who was at the time with Strathclyde University (now with the University of Dundee). Niamh had made an unsolicited, but as it turned out well‐timed, comment that the trace evidence community really needed a reference book. Within a day Niamh invited a friend and colleague from Wiley to meet with the three of us. The Wiley representative was very interested in our initial pitch and invited us to write a book proposal and so the journey that has resulted in this book properly began.

The concept of the book was developed around the need for updated information in the disciplines of trace evidence. No specific dedicated book has been devoted to trace evidence materials in years, making many existing reference texts out of date, particularly in light of the many changes and challenges that have occurred in regards to forensic science over the past decade. These changes have included the increased awareness of validation, modern methods for addressing and controlling contamination, the shift toward incorporating statistical analyses into the interpretation phase, and cutting edge research into new forensic science methods and their application. Criticism of some areas of trace evidence and court room testimony have also occurred and the need for the creation of standards and the development of regulatory bodies have been stressed and highlighted.

We tasked our authors to address several of these challenges in their opening remarks and answer many of the misunderstandings relating to trace evidence. This volume covers many of the foundational trace evidence and forensic science concepts, including having an approach to the collection of materials from scenes which considers the scientific implications, an in‐depth chapter on microscopy, and a “first of its kind” chapter on interpretation. The technical chapters chosen include paint and polymers, glass, fibers, and hair analysis.

We selected our authors so as to reach out to current practitioners and academics who are leaders in the field of trace evidence and forensic science. The reader will also see that for many of the chapters the authors have been paired. By partnering a North American author(s) and international author(s) we believe this has broadened and enriched the concepts discussed. Many of the authors have used their networks to gather information for the text and have acknowledged those individual contributions at the end of their chapters. We feel that the collection of authors and their knowledge of the subject areas make this trace evidence resource extremely valuable.

In addition to updating the information on the current practices in trace evidence, the authors were asked, where practical, to discuss suggested workflows in method and testing selections. With the increase in the criticism of forensic science, several of the chapters address the specific scientific challenges and limitations, including the limitations of our knowledge of the transfer, persistence, and background abundance of trace materials. This open approach is one which our authors readily embraced and is something which has been limited or non‐existent in previous texts. Addressing the challenges and limitations is critically important to understanding of how trace evidence can still play a significant role in investigations and legal proceedings.

This reference is designed and planned to serve the purpose of both classroom education and as a comprehensive guidance document for entry level examiners. The information provided may also be of use for attorneys and other criminal justice professionals who may need to gain some insight into the practices within the field. Furthermore, the book provides updated information in several disciplines of trace evidence which have not been offered for years.

The final overarching goal of this reference brings us back to the initial concept discussion between Vinny and Chris. In support for the future of trace evidence, this publication demonstrates how trace evidence continues to provide a valuable contribution within forensic science. The recognition and collection of trace evidence materials, its analysis through many technical disciplines, and the interpretation of the analytical findings within the context of a given case have the potential to make significant impact. The importance of this information cannot be stressed enough. If trace evidence materials are never recognized or are destroyed during handling or are never analyzed, then clearly no additional information can be obtained.

We hope you enjoy the collection of chapters in this book and find them useful in understanding the significance of trace evidence analysis and that you find the book to be a valuable reference for your personal or organization's library.

Finally, we are indebted to each and every one of our authors for their patience, dedication, and willingness to so freely share their knowledge and expertise, and provide an invaluable investment into the future generations of forensic trace examiners. We thank also the fantastic team at Wiley for their invaluable help in getting this book over the line and onto the shelves.

Vincent “Vinny” DesiderioChris E. TaylorNiamh Nic Daéid

1Trace Evidence Recognition, Collection, and Preservation

Ted R. Schwartz, Daniel S. Rothenberg, and Brandi L. Clark

Westchester County Forensic Science Laboratory, Valhalla, New York, USA

1.1 Introduction

Trace evidence is often not visible to the human eye, therefore it is typically the least understood and, unfortunately, the most overlooked form of evidence at the crime scene, and surprisingly even within the forensic laboratory. Some police officers, scene investigators, and laboratory personnel have a poor understanding of trace evidence. Proper knowledge is essential so that valuable trace evidence does not become lost, contaminated or accidentally transferred to another surface. Such incidents could severely hinder a successful criminal investigation. The goal of this chapter is to provide a foundation of knowledge that will enable successful processing of trace evidence in the forensic field. The following trace evidence principles will be discussed:

theories of transfer and persistence

proper trace evidence handling practices

recognition, collection, and preservation of trace evidence at the crime scene

recognition, collection, and preservation of trace evidence in the laboratory.

1.2 Theories of Transfer and Persistence

1.2.1 Locard's Exchange Principle

Edmond Locard (1877–1966), an early pioneer of forensic science, developed one of its most fundamental principles. His Exchange Principle theorizes that there will be a transfer of material every time contact is made between two surfaces, therefore during the commission of a crime, where contact is inevitable, it stands to reason that there will normally be some transfer of meaningful evidence. It could be in the form of hairs left by the perpetrator, either at the scene or on the victim. It might be fibers from a carpet at the scene or glass from a broken window that was transferred to the perpetrator's clothes. Crime scene events vary greatly and so will the theoretical transfers; thus explaining the difficulty in finding evidence of these transfers.

Another expression of Locard's Exchange Principle is this: When two surfaces make contact, material from one surface is transferred to the other surface and vice versa. Thus, there is always a potential for a two‐way transfer. At a crime scene, there should (in theory) be material transferred from the perpetrator to the scene, as well as material from the scene to the perpetrator. In reality, one of these types of transfers is more obvious than the other. Intuitively, it is easier to notice items/materials that may have transferred to the scene because they seem foreign or out of place. It is less obvious to consider what items/materials may have been taken away from the scene. A question that crime scene investigators or laboratory analysts often ask themselves is: “What material was transferred onto the surface of the item I am currently examining?” An area rug at a crime scene provides a good example. It is often not too difficult to see transferred material such as possible blood, broken glass or soil.

The more difficult and sometimes forgotten question has to do with the vice versa aspect of the Exchange Principle: “What may have come into contact with this item and caused a transfer from this item to another surface?” In the example of the area rug, there may be fibers from the rug that transferred to the shoes or clothing of any individual who came into contact with the rug. If so, then it is necessary to take known exemplar fibers from the rug. These exemplar fibers would be necessary for a comparison should relevant fibers be recovered from other items in the future.

When finding evidence of one item being transferred to another, there is always the question of what other potential items could have transferred that same material. One of the best trace evidence scenarios occurs when there is a two‐way transfer. In other words, when there are indications that trace evidence from one surface transferred to the other surface and vice versa. A good example of this sometimes develops in pedestrian hit‐and‐run collisions. Generally, the victim's clothing is searched for paint chips that may have been transferred from the striking vehicle (the vehicle to person transfer). Conversely, when a suspect vehicle is found, it is typically searched for hairs, fibers or other trace evidence that could have originated from the victim (the person to vehicle transfer). There are many cases in which paint chips are found on the victim's clothing that are similar to the paint on the suspect vehicle and fibers are found on the vehicle that are similar to the victim's clothing. When a two‐way transfer such as depicted in Figure 1.1 occurs and there is evidence that each surface/item was involved, the significance of the association is greatly increased.

1.2.2 Primary, Secondary, Tertiary, etc. Transfers

Establishing that a transfer may have occurred is only one aspect of trace evidence examination. The significance of this transfer can often be difficult to understand. Finding transferred evidence on an item of evidence does not necessarily mean that there was direct contact between the item and the source of the transferred material. The following section describes ways in which trace evidence can be transferred and an understanding of these concepts will lead to better assessments of any trace evidence found at a scene or in the laboratory.

A primary transfer occurs when trace evidence from a particular source is deposited directly onto another surface. For example, assume a woman is wearing a sweater composed of orange acrylic fibers that are easily shed. Her husband, who is wearing a blue sweater, gives her a hug. Numerous orange fibers from the wife's sweater are transferred to the husband's sweater. This is a primary transfer, since the transferred orange fibers on the husband's sweater were a result of direct contact with the wife's sweater.

A secondary transfer occurs when previously transferred trace evidence is transferred to yet another surface. Using the same example, assume that the husband now enters his vehicle and drives away. When he reaches his destination, he exits the vehicle, leaving some of the previously transferred orange fibers on the driver seat. Now assume that the orange fibers on the seat are compared to known fibers from the wife's sweater. What is the significance of a fiber match in this example? If one did not know that the husband was the driver of the vehicle, it might be theorized that the woman herself was in the driver seat due to the matching orange fibers. The orange fibers in the driver seat, however, were not transferred there as a result of direct contact with the source (the orange sweater), but rather as a result of a secondary transfer from the husband's clothing.

Figure 1.1 An example of a two‐way transfer. (a) An article of clothing being slammed into a board with wet paint. (b) Fibers transferred to the board. (c) Paint transferred to the fabric.

Continuing with the scenario, imagine a man breaking into the vehicle and stealing it. As he sits in the car, some of the orange fibers are yet again transferred, this time to his pants. When he gets to his destination, he exits the vehicle. An examination of his pants would likely reveal orange fibers. Again, there may be an assumption that this individual came into direct contact with the woman's sweater, despite knowing that was not the case. This is an example of a tertiary transfer, when evidence is transferred three times: an initial transfer and then twice more. If the car thief re‐deposits the orange fibers to yet another surface, that would be considered a quaternary transfer, and so on. These examples demonstrate that just because a potential source of trace evidence is established, it does not necessarily mean that two items were in direct contact with each other. The concept of multiple transfers should be explained to the police, the lawyers, and/or the triers of fact in a particular case so that they are able to arrive at proper conclusions.

Interestingly, the primary, secondary, and tertiary transfers in the presented scenario all followed Locard's Exchange Principle. However, the key point was whether or not the contact was made with the original source of the trace evidence. Only the primary transfer involved the original source (the wife's sweater in the example). Subsequent transfers occurred with other objects which happened to have the already transferred orange fibers on them.

1.2.3 Non‐contact Transfers

While Locard's Exchange Principle deals with contact between two surfaces, not all transfers occur due to direct contact. There are many instances in which trace evidence becomes airborne and then falls onto a surface. Think of breaking a window. Broken glass can travel several feet, potentially landing on any nearby surface (see Figure 1.2). If, for example, there was a jacket on the floor near the window, glass fragments might be deposited. If glass were to be found on the jacket in a subsequent laboratory examination, one might incorrectly conclude that whoever broke the window must have been wearing the jacket at the time.

Figure 1.2 A sheet of plate glass being broken by a hammer. The broken glass could potentially land on items several feet away.

Source: Courtesy of Keith Mancini, Westchester County Forensic Laboratory.

Numerous types of transfers can occur without direct contact. Shed hairs and fibers, chipping paint, soil dropped or kicked from shoes, and primer and propellant particles from a discharging firearm are additional examples.

1.2.4 Patterns Due to Contact

The transfer of material that can occur when contact is made between surfaces sometimes results in an impression pattern. Footwear, tires, fabric, and tools are examples of items that have the potential to impart impression patterns. The pattern on the receiving surface corresponds directly to the surface features of the other item. When someone steps onto a floor with a muddy shoe, the mud can transfer to the surface of the floor in a manner that preserves the design of the shoe's outsole (see Figure 1.3). While the mud itself can be useful as soil evidence, the impression pattern of the deposited mud is often of greater importance. If there are indications of deposited material on a piece of evidence, it is important to document it and to determine whether there is an impression pattern present. If so, comparisons can be made between the impression pattern and any item suspected of depositing the material.

Figure 1.3 A muddy shoe (a) and a muddy impression (b).