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Hair Analysis

Hair Analysis. It’s Everywhere!!!. Forensic hair examinations and comparisons are often used as important investigative and associative information Individual Evidence: evidence which can only be linked to one person Class Evidence: evidence that can be linked to a group of people

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Hair Analysis

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  1. Hair Analysis It’s Everywhere!!!

  2. Forensic hair examinations and comparisons are often used as important investigative and associative information • Individual Evidence: evidence which can only be linked to one person • Class Evidence: evidence that can be linked to a group of people • Hair evidence is class evidence When is it used?

  3. Hair is: • readily available • easily transferred • difficult to destroy Why is hair evidence used?

  4. If the source is animal or human • Race (sometimes) • Where on the body the hair came from • Whether the hair was forcibly removed • If the hair has been treated with chemicals • If drugs have been taken into the body What can be determined from hair?

  5. Hair of Infant

  6. Hair of Adult Female

  7. Hair Adult Male

  8. Arm Hair Adult Male

  9. Beard Hair

  10. Cuticle: outside covering of the hair; made of overlapping scales • Cortex: Inner layer made of keratin and imbedded with pigment (color) • Medulla: inside layer running down the center of the cortex Parts of the Hair

  11. Scales differ between species of animals and are named based on their appearance. Cuticle Scale Patterns

  12. 1. paint clear fingernail polish on a glass slide 2. when the polish begins to dry, place a hair on the polish 3.when almost dry, lift off the hair and observe the scale imprints Steps to Visualizing Human Scales

  13. Intermittent or interrupted • Fragmented • Continuous • Stacked • Absent—not present Types and Patterns of Medulla

  14. Human medulla may be continuous, fragmented or absent Human Medulla

  15. Determined by measuring the diameter of the medulla and dividing it by the diameter of the hair. • Medullary Index for human hair is generally less than 1/3. • For animal hair, it is usually greater than 1/2. Medullary Index

  16. Hair can be straight, curly or kinky depending on the cross-section of the hair What gives hair its shape?

  17. Terminology • Anagen—hair that is actively growing; lasting up to 5 years • Catagen—hair is not growing; a resting phase • Telogen—hair that is dying and ready to fall out; lasting two to six months • Grows about 0.5 mm per day or 1 centimeter per month; approximately one half inch per month Hair Growth

  18. Scale types Presence or absence of medulla Medullary type Medullary pattern Medullary index • Color • Length • Diameter • Distribution, shape and color intensity of pigment granules • Dyed hair has color in cuticle and cortex • Bleaching removes pigment and gives a yellow tint Comparing Hairs

  19. Cut with Razor Cut with Scissors Examples of Hair Basics

  20. More Hair BasicsNaturally Shed, Buckling and Forcibly Pulled Pulled & Broken Naturally Shed Forcibly pulled with tissue attached

  21. Burned Other Hair DamageFire Damage Buckling

  22. Questioned hairs must be accompanied by an adequate number of control samples • From victim • From possible suspects • From others who may have deposited hair at the scene Control Sample: a group of known materials used for comparison Collecting Hair

  23. Nuclear DNA- if tissue is still attached from being forcibly removed-traces to individual • Mitochondrial DNA- if not forcibly removed- shows only DNA inherited from the mother- traces to maternal line DNA from Hair

  24. Toxicology: the study of the nature, effects and detection of poisons and the treatment of poisoning • Advantages of Hair Toxicology: • Easy to collect and store • Externally available • Can provide information on the individual’s history of drug use or poisoning Collections from all areas of the body can give an accurate timeline of exposure or use Hair Toxicology

  25. Napoleon died in exile in 1821. By analyzing his hair, some investigators suggest he was poisoned by the deliberate administration of arsenic; others suggest that it was vapors from the dyes in the wallpaper that did him in. Case Study: Napoleon

  26. On October 3, 1849, Poe was found delirious on the streets of Baltimore, Maryland, "in great distress, and ... in need of immediate assistance", according to the man who found him, Joseph W. Walker.[He was taken to the Washington College Hospital, where he died at 5 a.m. on Sunday, October 7. Poe was never coherent enough to explain how he came to be in this condition. Some believe he was poisoned as a part of a political election corruption scheme Case Study: Edgar Allan Poe

  27. For additional information about hair and other trace evidence, check out Court TV’s Crime Library at: www.crimelibrary.com/criminal_mind/forensics/trace/1.html More About Hair

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