1. Forensic Science Chapter 8
Hair Analysis
Forensic Science
Chapter 8

2. What do you know?
Can the body area from which hair originated by determined?
Yes – with little difficulty
Pigment distribution, cross-section shape, diameter
Can the racial origin of hair be determined?
Rule of thumb:
Caucasian
Straight, wavy; even-pigment; oval-round cross section
African-American
Kinky; dense; uneven pigment

3. What do you know?
Can the age and sex of an individual be determined from a hair sample?
Age – NO (except infant hair – fine, short)
Sex – NO (can get ideas – bleached hair)
Is it possible to determine if hair was forcibly removed from the body?
Yes – follicular tag will remain if forcibly removed

4. What do you know? Are efforts being made to individualize human hair?
Nuclear DNA – both parents
Mitochondrial DNA – from mother  child
Can DNA individualize human hair?
Nuclear DNA – 1 in billions
mDNA – can exclude but not individualize!

5. FYI Hair is class evidence Avg human body has 5 million hairs
Head hairs:
Blondes have most – 120,000
Redheads – 80,000
Black/brown – 100,000
Constantly shedding and replacing hairs – 100 per 24 hour period (scalp)

6. Morphology of Hair Morphology – form and structure of hair
Clues in Crime CD – 5.2
Made up of polymers – complex long-chained molecules
Very resistant to breaking down
Grows from hair follicle – a tubelike organ in the dermis
Hair root embedded in follicle
Follicle is linked to body’s blood supply – everything is distributed into hair

7. Morphology of Hair Hair shaft – extends out through epidermis
Three parts
Cuticle
Cortex
Medulla

8. Morphology of Hair Cuticle Function Clear outside covering of shaft
Helps resist chem decomposition
Helps retain structure
Clear outside covering of shaft
Made up of tough, overlapping scales (points towards tip of hair)
Formed by cells that have hardened (keratinized) then flattened
Help in species ID
Humans – much finer pattern; not much variation
Animals – vary from species to species
See scales?
SEM
Cast

9. Morphology of Hair Cuticle cont Three basic patterns: Coronal Spinous
Imbricate

10. Morphology of Hair Coronal Crown-like
Found in hairs of very fine diameter and resembles a stack of paper cups
Small rodents and bats but not in human hairs

11. Morphology of Hair Spinous
Petal-like scales are triangular in shape and protrude from the hair shaft
Fur hairs of seals, cats, and some other animals. They are never found in human hairs

12. Morphology of Hair Imbricate
Flattened-scale type of overlapping scales with narrow margins
They are commonly found in human hairs and many animal hairs

13. Morphology of Hair
Coronal, Spinous, or Imbricate??

14. Morphology of Hair Cortex
Made up of keratin (tough protein polymer made up of about 20 different amino acids)
Contains color pigment – Melanin
Eumelanin - responsible for black and brown color
Phaeomelanin - responsible for red shades
Blondes – low amounts of melanin – shade of blonde depends on what type of melanin you have
Absence of pigment = gray or white hair
Cortical fusi – little sacs of air
Come in different size and shapes
Can see under a magnification of 100x

15. Morphology of Hair Medulla
Cellular column through center of hair – like a canal or spinal cord; no known function
Predominant feature of hair
More than ½ of diameter of hair
Medullary index – calculated to help ID species
Medullary index = diameter of medulla
diameter of hair shaft
Expressed as a fraction
Humans < 1 3
Others > 1 2

16. Morphology of Hair Medulla – cont Varies extensively
NOT all hairs have one
Types:
Continuous
Interrupted/Intermittent – even breaks
Fragmented (segmented) – uneven breaks
Absent
Humans normally – absent or fragmented

17. Morphology of Hair Medulla Cont Patterns Uniserial - Cat
Multiserial - Rabbit
Lattice - Deer
Vacuolated - Dog
Amorphous - Human

18. Morphology of Hair Shape of hair Straight, curly, kinky
Depends on cross-section of the hair shaft
Round – straight hair
Less Round– curly hair
Oval/Elliptical– kinky hair
Generalizations:
Asians/Native Americans – round, no twisting
American/European whites, Mexicans, Middle East – less round, rare twist (undulation), evenly distributed pigment
African – oval or elliptiacl, twist, clumped pigmentation

19. Morphology of Hair Hair Root Grows at about 1cm/month
Three stages of growth
Anagen Phase
Catagen Phase
Telogen Phase

20. Anagen Phase Lasts up to five years
Includes 80-90% of hair follicles at any one time
Initial growth
Hair bulb attached to blood supply

21. Catagen Phase Intermediate Phase Lasts 2-3 weeks
Hair bulb  Detached from blood supply

22. Telogen Phase Lasts 2-6 months 8-10% of all hair follicles
Sheds hair naturally
Follicular Tag – tissue pulled with hair; contains DNA

23. Summary of Hair Growth

25. Morphology of Hair Hair Tip External End Mature Hair
Will taper to a point
Cut Hair
Will be squared off (but within 2-3 weeks will become rounded)
Frayed or split ends
Dryness or lack of care

26. Identification and Comparison of Hair
Identify
Race
Generally – yes, by cross-sectional shape
Age
No – except infants
Sex
No – can generalize
Forcibly Removed?
Yes – more tissue = more force

27. Identification and Comparison of Hair
Compare
Scale structure
Medullary index
Medullary shape
Color
Length
Diameter
Pigment intensity
Infections/abnormalities

28. Hair as a Chemical Indicator
Many drugs and their metabolites (specific product of drug interaction with body) can be detected in just a few mm of hair
Because of hair slow growth – longer periods of drug use can be detected
Metal content
Diagnose dietary deficiencies and disease
Poisoning
Hg, Pb, As

29. Hair as a Chemical Indicator
Person’s environment
Scalp oils can find traces of environment
Detect smoke from crack cocaine, industrial pollution

30. Collection and Preservation of Hair
Always accompanied by reference samples
Normally need
50 scalp hairs
Full length
Pull out or clip at skin line
24 pubic hairs

31. Case Study Ennis Cosby – 1997 27 years old
Got a flat tire – pulled off the road to put spare – Bel-Air
Shortly after – an assailant demanded money and when Ennis didn’t respond quickly enough, was shot in the temple
A .38 revolver was later found miles from the scene

32. Case Study
Mikail Markhasev (Ukranian immigrant – age 19) was arrested and charged with murder
Hair was recovered from Ennis’s hat
Identified 6 DNA markers from tissue that matched Markhasev’s DNA
Markhasev was convicted of murder
serving life sentence without
possibility of parole

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

34. Case Study
John Vollman
Clues in Crime CD

35. Wrongful Accusation