{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

Hair evidence is class evidence

When is it used?

Hair is:a. readily availableb. easily transferredc. difficult to destroy

Why is hair evidence used?

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?

Hair of Infant

Hair of Adult Female

Hair Adult Male

Arm Hair Adult Male

Beard Hair

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

Scales differ between species of animals and are named based on their appearance.

Cuticle Scale Patterns

1. paint clear fingernail polish on a glass slide2. when the polish begins to dry, place a hair on the polish3.when almost dry, lift off the hair and observe the scale imprints

Steps to Visualizing Human Scales

Intermittent or interrupted

Fragmented Continuous Stacked Absent—not present

Types and Patterns of Medulla

Human medulla may be continuous, fragmented or absent

Human Medulla

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

Hair can be straight, curly or kinky depending on the cross-section of the hair

What gives hair its shape?

TerminologyAnagen—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

{ { 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

Scale types Presence or

absence of medulla

Medullary type

Medullary pattern

Medullary index

Comparing Hairs

Examples of Hair Basics

Cut with Scissors

Cut with Razor

More Hair BasicsNaturally Shed, Buckling and Forcibly Pulled

Naturally Shed

Pulled & Broken

Forcibly pulled with tissue attached

Other Hair DamageFire Damage

Buckling

Burned

Questioned hairs must be accompanied by an adequate number of control samples

a. From victimb. From possible suspectsc. From others who may have deposited

hair at the scene

Control Sample: a group of known materials used for comparison

Collecting Hair

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

Hair Toxicology

Toxicology: the study of the nature, effects and detection of poisons and the treatment of poisoning

Advantages of Hair Toxicology:a. Easy to collect and storeb. Externally availablec. 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

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

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

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