1. Hairs and Fibers

2. Morphology and Structure of Hair

3. Morphology (Structure) of Hair An appendage of the skin that grows out of an organ known as the hair follicle. An appendage of the skin that grows out of an organ known as the hair follicle. Extends from its root or bulb embedded in the follicle, continues into a shaft, and terminates at a tip end. Extends from its root or bulb embedded in the follicle, continues into a shaft, and terminates at a tip end.

4. The Shaft of Hair Composed of three layers: cuticle, cortex, and medulla. Composed of three layers: cuticle, cortex, and medulla.

5. Morphology: Cuticle Protective coating made of overlapping scales, produce a characteristic pattern Protective coating made of overlapping scales, produce a characteristic pattern Scales always point toward tip of hair Scales always point toward tip of hair Not useful in individualizing human hair Not useful in individualizing human hair Can be used for species identification Can be used for species identification http://www.pg.com/science/haircare/hair_twh_35/hair_twh_35_02.jpg

6. Preserving scale pattern Since examination of internal structure of hair requires loss of scale pattern, a scale case is made. Since examination of internal structure of hair requires loss of scale pattern, a scale case is made. Clear nail polish on microscope slide Clear nail polish on microscope slide Hair embedded and allowed to dry before removed. Hair embedded and allowed to dry before removed.

7. Differences between animal hairs & human hairs There are three basic scale structures that make up the cuticle: There are three basic scale structures that make up the cuticle: 1. coronal (crown-like) 2. spinous (petal-like) 3. imbricate (flattened) Combinations and variations of these types are possible. http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm

8. Differences between animal hairs & human hairs 1. Coronal, or crown-like scale pattern: 1. Coronal, or crown-like scale pattern: hairs of very fine diameter hairs of very fine diameter resemble a stack of paper cups resemble a stack of paper cups commonly found in the hairs of small rodents and bats, but rarely in human hairs commonly found in the hairs of small rodents and bats, but rarely in human hairs http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm

9. Differences : animal hairs & human hairs 2. Spinous or petal-like scales:  triangular in shape and protrude from the hair shaft  are found at the proximal region of mink hairs and on the fur hairs of seals, cats, and some other animals  never found in human hairs http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm

10. Differences between animal hairs & human hairs 3. Imbricate or flattened scales:  consist of overlapping scales with narrow margins  commonly found in human hairs and many animal hairs

11. Differences between animal hairs and human hairs Human hairs are generally consistent in color; whereas animal hairs may exhibit radical color changes in a short distance, called banding. Human hairs are generally consistent in color; whereas animal hairs may exhibit radical color changes in a short distance, called banding. The pigmentation of human hairs is evenly distributed, or slightly more dense toward the cuticle; whereas the pigmentation of animal hairs is more centrally distributed, although more dense toward the medulla. The pigmentation of human hairs is evenly distributed, or slightly more dense toward the cuticle; whereas the pigmentation of animal hairs is more centrally distributed, although more dense toward the medulla.

12. Morphology: Cortex Made of spindle-shaped cells aligned in a regular array, parallel to the length of the hair Made of spindle-shaped cells aligned in a regular array, parallel to the length of the hair Embedded with pigment granules that give hair its color Embedded with pigment granules that give hair its color The color, shape and distribution of the granules provide points for forensic comparison The color, shape and distribution of the granules provide points for forensic comparison www.pg.com/science/haircare/hair_twh_59.htm

13. Your natural Hair color is determined by three factors 1. The type of natural color pigment melanin present in your hair's cortex. Eumelanin (black pigment) Eumelanin (black pigment) Phenomelanin (red/yellow pigment) Phenomelanin (red/yellow pigment) 2. Number of melanin granules 3. Spacing of those granules (close together or far apart)

14. How Melanin pigments determine your natural hair color: Black hair: densely packed melanin granules, full of eumelanin Black hair: densely packed melanin granules, full of eumelanin Brown hair: loose pattern of eumelanin-filled granules or granules blended with eumelanin and phenomelanin Brown hair: loose pattern of eumelanin-filled granules or granules blended with eumelanin and phenomelanin Blonde hair: few granules with minimal bits of eumelanin… In fact, the eumelanin is so sparse that the color of blonde hair is the color of the hair fiber itself. Blonde hair: few granules with minimal bits of eumelanin… In fact, the eumelanin is so sparse that the color of blonde hair is the color of the hair fiber itself. Red hair: loosely packed granules containing phenomelanin Red hair: loosely packed granules containing phenomelanin

16. What causes gray hair? As you age, your natural production of pigment slows down and your natural color loses its color strength. As you age, your natural production of pigment slows down and your natural color loses its color strength. This doesn't happen to every hair at the same time, so the contrast between the hair with no color and the hair that still has some color causes it to look gray. This doesn't happen to every hair at the same time, so the contrast between the hair with no color and the hair that still has some color causes it to look gray. So how gray your hair actually looks is determined by the percentage of strands with no color vs. the pigmented strands. So how gray your hair actually looks is determined by the percentage of strands with no color vs. the pigmented strands.

17. Morphology: Medulla Canal-like structure of cells that runs through the center of the cortex Canal-like structure of cells that runs through the center of the cortex

18. Medullary Index Measure of the diameter of the medulla relative to the diameter of the hair shaft Measure of the diameter of the medulla relative to the diameter of the hair shaft Usually expressed as a fraction Usually expressed as a fraction Humans: medullary index < 1/3 Humans: medullary index < 1/3 Animals: medullary index > 1/2 Animals: medullary index > 1/2

19. Medullae of Different Species

20. Medulla Shape Medulla shape is another characteristic that varies from species to species Medulla shape is another characteristic that varies from species to species UNISERIAL (rabbit) MULTISERIAL (rabbit) VACUOLATED (dog, fox, common) LATTICE (deer) AMORPHOUS (human, common) 20

21. Medulla of Different Species

22. Forensic Analysis of Medulla Presence of medulla varies quite a bit: even hair to hair Presence of medulla varies quite a bit: even hair to hair Human head hairs generally have no medulla or may be fragmented ones; except Mongoloid (Asian) race whose medulla is usually continuous Human head hairs generally have no medulla or may be fragmented ones; except Mongoloid (Asian) race whose medulla is usually continuous Most animals have medulla that is continuous or interrupted Most animals have medulla that is continuous or interrupted The shape of the medulla can help identify a species The shape of the medulla can help identify a species Examples: Examples: Most animals and humans: cylindrical Most animals and humans: cylindrical Cats: string of pearls Cats: string of pearls Deer: spherical occupying whole hair shaft Deer: spherical occupying whole hair shaft

23. Comparison of Animal and Human Hair Medullary Index ≥1/2 Medulla is present for all animals Medulla is continuous for most animals Medulla is patterned for most animals The pattern can tell the species! Medullary Index <1/3 Medulla is absent for most humans Medulla is continuous for Mongoloid race Medulla is fragmented – only some animals and humans Medulla is cylindrical in shape (most animals)

24. Identification and Comparison of Hair Morphological Characteristics do not allow individualization of a human hair to any single head or body Morphological Characteristics do not allow individualization of a human hair to any single head or body Hair when collected with an adequate number of standards/references can provide strong circumstantial evidence Hair when collected with an adequate number of standards/references can provide strong circumstantial evidence Scale structure, medullary index, and medullary shape are most often used for hair comparison Scale structure, medullary index, and medullary shape are most often used for hair comparison

25. Human Hairs (Testify) Racial Determination Racial Determination Body Area Body Area Age and Sex? Age and Sex? Forcibly Removed? Forcibly Removed?

26. Can the racial origin of hair be determined? Forensic terms: Caucasoid, African/West India, Mongoloid Forensic terms: Caucasoid, African/West India, Mongoloid Mongoloid has continuous medullae Mongoloid has continuous medullae Caucasian has even distribution of pigment in cortex Caucasian has even distribution of pigment in cortex African/West India has unevenly distributed pigment. African/West India has unevenly distributed pigment. http://www.fbi.gov/hq/lab/fsc/backissu/july2000/deedric1.htm

27. Racial Determination African Mongoloid Caucasoid Usually kinky, containing dense, unevenly distributed pigments. Cross section is flat to oval in shape. Usually straight or wavy with very fine to coarse pigments that are more evenly distributed. Cross section are oval to round in shape. Usually coarse containing pigment granules larger in size than Caucasians. Cross sections are round in shape. Cross section varieties.

28. Head Hairs Long with moderate shaft diameter and diameter variation Long with moderate shaft diameter and diameter variation Medulla absent to continuous and relatively narrow when compared to the structure of hairs from other body areas Medulla absent to continuous and relatively narrow when compared to the structure of hairs from other body areas Often with cut or split tips Often with cut or split tips Can show artificial treatment, solar bleaching, or mechanical damage Can show artificial treatment, solar bleaching, or mechanical damage Soft texture, pliable Soft texture, pliable

29. Pubic Hairs Medulla relatively broad and usually continuous when present Root frequently with tag Tip usually tapered, rounded, or abraded Stiff texture, wiry Shaft diameter coarse with wide variations and buckling

30. Limb Hairs Tips usually tapered, often blunt and abraded, rounded scale ends due to wear Diameter fine with little variation Gross appearance of hair is arc-like in shape Medulla is discontinuous to trace with a granular appearance Soft texture

31. Facial Hairs (Beard/Mustache) Diameter very coarse with irregular or triangular cross-sectional shape Diameter very coarse with irregular or triangular cross-sectional shape Medulla very broad and continuous, may be doubled Medulla very broad and continuous, may be doubled

32. Chest Hairs Shaft diameter moderate and variable Shaft diameter moderate and variable Tip often darker in color, long and fine, arc-like Tip often darker in color, long and fine, arc-like Medulla may be granular Medulla may be granular Stiff texture Stiff texture

33. Axillary or Underarm Hairs Resemble pubic hairs in general appearance, but less wiry Resemble pubic hairs in general appearance, but less wiry Medullary appearance similar to limb hairs Medullary appearance similar to limb hairs Diameter moderate and variable with less buckling than pubic hairs Diameter moderate and variable with less buckling than pubic hairs Tips long and fine, frequently with bleached appearance Tips long and fine, frequently with bleached appearance

34. Other Body Hairs Eyebrow: Stubby, some diameter fluctuation, saber-like in appearance Eyebrow: Stubby, some diameter fluctuation, saber-like in appearance Eyelash: Short, stubby with little shaft diameter fluctuation, saber-like in appearance Eyelash: Short, stubby with little shaft diameter fluctuation, saber-like in appearance Trunk: A combination of features of limb and pubic hairs, a transitional hair Trunk: A combination of features of limb and pubic hairs, a transitional hair

35. Tip of the Shaft Burned Cut Razored Split

36. Root of Hair Provide the tools to produce hair and continue its growth Provide the tools to produce hair and continue its growth 3 Stages of Growth (different looking roots) 3 Stages of Growth (different looking roots) Anagen -initial phase may last up to 6 years, root is flame shaped Anagen -initial phase may last up to 6 years, root is flame shaped Catagen –transition phase (2-3 weeks), root is elongated Catagen –transition phase (2-3 weeks), root is elongated Telogen –phase where hair naturally falls out of the skin, root is club-shaped Telogen –phase where hair naturally falls out of the skin, root is club-shaped

37. HairHair Growth Cycle Hair

38. Forcibly Removed? Pulled Forcibly Removed Shed

39. A normal telogen hair with a hard 'club' end, seen under (left) a light microscope and (right) an electron microscope An anagen hair that has been plucked out: notice the soft, sticky tail Brushed-out hairs all have this kind of root. This is an anagen hair, one which was pulled out and not ready to be shed.

40. Collection of Hair Evidence

41. Questioned and Reference hair must come from same area of the body; one cannot, for instance compare head hair to pubic hair. Questioned and Reference hair must come from same area of the body; one cannot, for instance compare head hair to pubic hair. The collection of 50 full length hairs from all areas of the scalp will normally ensure a representative sampling of head hair. The collection of 50 full length hairs from all areas of the scalp will normally ensure a representative sampling of head hair.

42. Collection of Hair Evidence A minimum collection of 24 full length pubic hairs should cover the range of characteristics present in this type of hair. A minimum collection of 24 full length pubic hairs should cover the range of characteristics present in this type of hair. All collected hairs must be full-length so that the investigator can see if the color and morphological features vary throughout the length of the hair. All collected hairs must be full-length so that the investigator can see if the color and morphological features vary throughout the length of the hair.

43. What does this mean…..? To victims of a Sexual Assault? To victims of a Sexual Assault? Do you think this would increase or decrease the likelihood that a person would file charges against their attacker?

44. Packaging of Hair Evidence Recover all hair present. If possible, use fingers or tweezers to pick up hair, place in paper bindles or coin envelopes which should then be folded and sealed in larger envelopes. Label the outer sealed envelope.

45. If hair is attached, such as in dry blood, or caught in metal or a crack of glass, do not attempt to remove it but rather leave hair intact on the object. If the object is small, mark it, wrap it, and seal it in an envelope. If the object is large, wrap the area containing the hair in paper to prevent loss of hairs during shipment

46. Fibers…. Fall into two main categories…. Fall into two main categories…. 1. Natural  non- synthetic 1. Natural  non- synthetic 2. Man- Made  synthetic 2. Man- Made  synthetic

48. Fibers: Natural---Non- synthetic Derived entirely from animal or plant sources Derived entirely from animal or plant sources Most prevalent plant fiber is cotton. Most prevalent plant fiber is cotton. Its widespread use has made its evidential value almost meaningless Its widespread use has made its evidential value almost meaningless Cotton has a ribbon-like shape with twists at regular intervals Cotton has a ribbon-like shape with twists at regular intervals Animal sources include sheep (wool), goats (mohair, cashmere) and many other sources Animal sources include sheep (wool), goats (mohair, cashmere) and many other sources http://www.swicofil.com/images/cotton_microscopic.jpghttp://www.e4s.org.uk/textilesonline/content/6library/report1/images/microscope_2.gif Wool Cotton

49. Linen - stem fiber from flax plant Kapok - from seed hairs of kapok plant Other fibers - Manila, hemp, sisal, jute Other Plant Fibers: Trace > Fibers > Natural Cotton Linen Hemp sisal jute

50. Mineral Fibers Asbestos - crystalline material  Used to be used for insulation  Fractures into thin rods that can get into your lungs; can kill you  Not used much anymore Trace > Fibers > Natural

51. Filament: Long continuous fiber (like silk) Staple: Filament is cut into smaller pieces; staples are spun together to form thread (like cotton) Trace > Fibers Filament vs. Staple

52. Man-Made Fibers: aka “Synthetic” Fibers derived from either natural or synthetic polymers Fibers derived from either natural or synthetic polymers The fibers are made by forcing polymeric material through the holes of a spinneret The fibers are made by forcing polymeric material through the holes of a spinneret Rayon and then nylon were the first two man-made fibers (year 1911) Rayon and then nylon were the first two man-made fibers (year 1911) http://www.naturalvisions.co.uk/pictures/thumbnail/XMIC_0021_0001XX.jpg

53. Man-Made Fibers Con’t Regenerated Fibers Regenerated Fibers Made from regenerated cellulose (wood or cotton pulp) Made from regenerated cellulose (wood or cotton pulp) Include such fibers as rayon, acetate, and triacetate Include such fibers as rayon, acetate, and triacetate Synthetic Fibers Synthetic Fibers Currently manufactured Currently manufactured Made from synthetic chemicals called polymers Made from synthetic chemicals called polymers Include such fibers as nylons, polyesters, and acrylics Include such fibers as nylons, polyesters, and acrylics

54. Class characteristics Trace > Fibers > Analysis Color: microscopic examination Size: length and width can be measured Shape: cross section is viewed

55. ID and Comparison of Man- Made Fibers Fabrics that can be fitted together at their torn edge are easy to match Fabrics that can be fitted together at their torn edge are easy to match Microscopic comparison of color and diameter Microscopic comparison of color and diameter Comparison of lengthwise striations and pitting on the surface of a fiber Comparison of lengthwise striations and pitting on the surface of a fiber The shape of the fiber—ex. Wayne Williams case The shape of the fiber—ex. Wayne Williams case Cross sections are generally helpful Cross sections are generally helpful Note: Combined factors of color, size, shape, microscopic appearance, chemical composition, and dye content make it very unlikely to find two different people wearing identical fabrics Note: Combined factors of color, size, shape, microscopic appearance, chemical composition, and dye content make it very unlikely to find two different people wearing identical fabrics

56. ID and Comparison of Man- Made Fibers con’t. The chemical makeup of the fiber itself can be examined through the following: Infrared microspectrophotometry Infrared microspectrophotometry Refractive Index Refractive Index The chemical makeup of the dyes in the fiber can be examined through the following: Liquid chromatography Liquid chromatography Visible light microspectrophotometry Visible light microspectrophotometry

57. Chemical Composition: determined by advanced instrumentation Trace > Fibers > Analysis Class characteristics

58. PaintForensics Forensics  What is paint?  What crimes are paint involved in?  How is paint collected?  How is paint analyzed in the lab?

59. What is paint?  Colored chemical coating  Covers cars and houses Trace > Paint

60. Paint contains 3 types of substances:  Vehicle – binds components together, adjusts the viscosity ( how well it flows)  Pigment – gives paint color  Extenders – used to modify gloss, texture, opacity, etc. What is paint? Trace > Paint

61. Automotive Paint Electrocoat primer – the first layer applied to the steel body of the car. Electrocoat primer – the first layer applied to the steel body of the car. * The primer consists of epoxy based resins which is electroplated onto the steel body of the automobile to provide corrosion resistance. * The primer consists of epoxy based resins which is electroplated onto the steel body of the automobile to provide corrosion resistance. * The color of these electrodeposition primers ranges from black to gray. * The color of these electrodeposition primers ranges from black to gray.

62. Automotive Paint Primer surfacer – layer of coating that usually follows the electrocoat layer and is applied before the base coat. Primer surfacer – layer of coating that usually follows the electrocoat layer and is applied before the base coat. *Primer surfacers are epoxy modified polyesters or urethanes. *Primer surfacers are epoxy modified polyesters or urethanes. ** This layer is highly pigmented. Color pigments are used so as to minimize color contrast between primer and topcoats. ** This layer is highly pigmented. Color pigments are used so as to minimize color contrast between primer and topcoats.

63. Automotive Paint Basecoat – layer that provides the color and aesthetics of the finish and therefore represents the “eye appeal” of the finished automobile. Basecoat – layer that provides the color and aesthetics of the finish and therefore represents the “eye appeal” of the finished automobile. **The integrity of this layer is dependent on its ability to resist the elements of weather, UV radiation and acid rain. **The integrity of this layer is dependent on its ability to resist the elements of weather, UV radiation and acid rain. There is also a growing trend toward pearl luster or mica pigments. There is also a growing trend toward pearl luster or mica pigments.

64. Automotive Paint:Making Paint Making PaintMaking Paint Mica pigments are coated with layers of metal oxide to generate interference colors. The addition of aluminum flakes to automotive paint will impart a metallic look to the paint’s finish.

65. Automotive Paint Clearcoat – An unpigmented clearcoat is applied to improve gloss, durability and appearance. Clearcoat – An unpigmented clearcoat is applied to improve gloss, durability and appearance. * Most clearcoats are acrylic based, but polyurethane clearcoats are increasing in popularity. * The clearcoat provides an * The clearcoat provides an outstanding etch resistance and appearance.

66. What crimes are paint involved in?  Hit and Runs – paint from car left at scene  Other vehicular accidents  Home invasion – windows; on suspect Trace > Paint

67. How is paint collected? How is paint collected?  Visually by hand or with forceps.  Packaged in sealed containers. Trace > Paint

68. How is paint analyzed? 1. Possibly a physical match (jigsaw-like) 2. Associate the unknown paint with a known sample (class characteristics) Trace > Paint

69. Chemical composition determined by FT-IR FTIR (Fourier Transform Infrared) Spectroscopy, or simply FTIR Analysis, is a failure analysis technique that provides information about the chemical bonding or molecular structure of materials, whether organic or inorganic. Trace > Paint > Analysis How is paint analyzed? Chemical “Fingerprint”

70. Paint can be in multiple layers Each layer is analyzed to determine its physical and chemical properties. Trace > Paint > Analysis