2. History of Hair Analysis
1910- Murder of Germaine Bichon
Rosella Rousseau confessed only after confronted with hair as evidence.
Hair found under Bichon’s fingernails.

3. For Discussion
What are the possible limitations of using hair as evidence in a crime investigation?
What are the possible advantages of using hair evidence?
What reasons might have prevented investigators from using hair in investigations before 1910?
What kinds of technology advances have made it possible for investigators to use hair as evidence?

4. Introduction Trace Evidence Most common examples: Hair Fiber
any small pieces of material, man-made or naturally occurring (animal, plant or mineral)
Most common examples:
Hair
Fiber

5. Test Questions for Trace Evidence
What is it?
Is it man-made or natural?
What is its source?
How common is it?
Can it be identified to a single source?

6. Hair
Human hair is one of the most frequently found pieces of evidence at the scene of a violent crime. It can provide a link between the criminal and the act.
From hair one can determine:
Human or animal origin
Body region
Manner in which hair was removed
Treated hair
Drugs ingested
BUT NOT- age or sex of origin
The age of an individual cannot be determined definitively by a microscopic examination; however, the microscopic appearance of certain human hairs, such as those of infants and elderly individuals, may provide a general indication of age. The hairs of infants, for example, are generally finer and less distinctive in microscopic appearance. As individuals age, hair can undergo pigment loss and changes in the configuration of the hair shaft to become much finer and more variable in diameter.

7. Biology of Hair Hair is composed of the protein keratin
which is also the primary component of finger and toe nails.
produced from a structure called the hair follicle
develop hair follicles during fetal development
no new follicles are produced after birth
color is mostly the result of pigment
chemical compounds that reflect certain wavelengths of visible light. 
Sources: &

8. shape (round or oval)texture (curly or straight)
influenced heavily by genes.
physical appearance of hair can be affected by nutritional status and intentional alteration (heat curling, perms, straightening, etc.)
The body area (head, arm, leg, back, etc.) from which a hair originated can be determined
using sample’s length, shape, size, color, and other physical characteristics.
In order to test hair evidence for DNA, the root must be present.

9. Hair Structure Hair is composed of three principal parts:
Cuticle – outer coating composed of overlapping scales
Cortex – protein-rich structure around the medulla that contains pigment
Medulla – central core (may be absent)
The structure of hair has been compared to that of a pencil with the medulla being the lead, the cortex being the wood and the cuticle being the paint on the outside.

10. Hair Stages Hair goes through phases- growth, resting, and dying/loss.
80-90% 2%
10-18%
The average period of growth for scalp hair is approximately 1,000 days the resting phase lasts about 100 days.
Approximately 10 percent of the hairs on a human head (100/1000) are in the quiescent telogen phase, and a minimal amount of force—such as that from combing—is required to dislodge the hairs from the dormant follicle.

11. Hair Growth Terminology
Anagen--hair that is growing
Catagen--hair at rest
Telogen--hair that is dying
Length mm per day or 1 centimeter per month; approximately one half to one inch per month

12. MORPHOLOGY OF HAIR Hair is often found at a crime scene
Must be properly collected and can then, be used as corroborative evidence
Hair is an appendage of the skin, and grows out from a HAIR FOLLICLE
Parts of hair are:
root (or bulb)
shaft
tip end
Shaft has 3 layers:
cuticle
cortex
medulla

13. Hair Morphology The Study of Structure and Form
Parts of the hair
Shaft--part of the hair that sticks out of the skin
Tip – end point of hair shaft
Root--lies below the epidermis
Follicle--structure from which the hair grows

14. Hair Structure Cuticle The cuticle varies in: scales
How many there are per centimeter
How much they overlap
Their overall shape
How much they protrude from the surface
thickness
Whether or not it contains pigment.
Characteristics of the cuticle may be important in distinguishing between hairs of different species but are often not useful in distinguishing between different people.
Info: Image:

15. THE CUTICLE Characteristics for good evidence
resistance to chemical decomposition
ability to retain structural features over long period of time
Cuticle is formed by overlapping scales that point toward the tip end
formed as special cells that keratinize (harden) and flatten as they form in the follicle
Pattern of the scales are sometimes useful in determining species of animal

16. Hair Cuticle outermost layer of hair which is covered with scales
Scales also always point toward the tip of the hair
scales differ between species of animals and are names based on their appearance
Some of these scales are variations of the same and include:
Mosaic
Pectinate
Imbricate
Petal
Diamond petal
Chevron

17. Cuticle Patterns Each species has different patterns.
Cannot determine the specific animal from the hair.

18. Scale Types
Mosaic
Chevron

19. Scale Types (cont)
Pectinate
Imbricate

20. Scale Types (cont)
Diamond Petal
Petal

21. Removal of Hair
When hairs originate from a body in a state of decomposition, a dark band may appear near the root of the hair. This characteristic has been labeled a postmortem root band.
Naturally shed
                     
                     
                     
                     
Forcibly removed
Forcibly removed with root tissue DNA test can be done

22. HUMAN SCALES In order to visualize the scales
paint fingernail polish on a slide
place a hair on the polish
lift off the hair and observe the scale imprints
What pattern is seen in this slide?

23. Human Cuticle
Tip
end
Tip end
Imbricate pattern

24. THE CORTEX This is the layer below the cuticle
Made up of spindle-shaped cortical cells that are parallel to the cuticle
Pigment granules here give hair its color
Color, shape, and arrangement of granules give points of comparison between individuals
Must use microscope to view the cortex

25. Hair Structure Cortex The cortex varies in: Thickness Texture Color
Distribution of the cortex is perhaps the most important component in determining from which individual a human hair may have come.
Microscopic examination can also reveal the condition and shape of the root and tip.
Info: Image:

26. Hair Cortex The cortex gives the hair its shape.
Wavy or curly hair is oval in cross section.
Kinky or woolly hair is flat in cross section
Straight-textured hair is round in cross section

27. THE MEDULLA Collection of cells that run in the center of the shaft
Many animals have a prominent medulla- humans do not
Medullae vary from person to person and from hair to hair
Medullae classified as:
continuous
interrupted
segmented
fragmented or absent
Humans usually have fragmented or absent medullae
Shape of medullae are also significant- usually cylindrical in humans but can be patterned in animals

28. Hair Structure Medulla The medulla may vary in: Thickness
Continuity - one continuous structure or broken into pieces
Opacity - how much light is able to pass through it
It may also be absent in some species.
Like the cuticle, the medulla can be important for distinguishing between hairs of different species, but often does not lend much important information to the differentiation between hairs from different people.

29. Hair Medulla
The medulla is the hair core, but is not always present. The medulla comes in different types and patterns.
Types:
Continuous
Intermittent or interrupted
Fragmented
Absent--not present

30. Medulla Patterns

31. Hair Medulla Patterns Uniserial Multiserial Vacuolated Lattice
Amorphous (without a distinct pattern)

32. Medulla Patterns in Different Species

33. HUMAN MEDULLA
Human medulla may be continuous, fragmented or absent.

34. Medullary Index
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.

35. IDENTIFICATION AND COMPARISON OF HAIR Using Comparison Microscope
In trials usually just identify hair as human or animal.
Identifying which human the hair belongs to is much harder.
Need many standards (samples) for comparison to suspect.
Can compare scalp or pubic hairs.
Again, probability that sample is phys. evidence from the suspect is the question in a trial.

36. Hair Comparison Color Length Diameter
Distribution, shape and color intensity of pigments granules
Dyed hair has color in cuticle and cortex
Bleaching removes pigment and gives yellow tint
Scale types
Presence or absence of medulla
Medullary type
Medullary pattern
Medullary index

37. Collection of Hair Evidence
Questioned hairs must be accompanied by an adequate number of control samples.
from victim
possible suspects
others who may have deposited hair at the scene
Control Sample
full-length hairs from all areas of scalp
25-50 full-length pubic hairs

38. IDENTIFICATION AND COMPARISON OF HAIR- Using Comparison Microscope
Age and sex CANNOT be determined by hair
sex can be determined by DNA analysis if root tissue is present
Hair root with follicular tissue may indicate hair was pulled out forcibly- by a person or comb
Currently trying to individuate hair by using mitochondrial DNA test.
Routinely collected during autopsy of victim of unnatural causes.

39. Animal Cuticles Human, Dog, Deer Rabbit, Cat, Horse

40. RABBIT MEDULLA
Rabbit medulla is different depending on the type (location on the rabbit) of hair. The one to the left is multiserial. The one to the right is a uniserial ladder and is found in guard hair.