Hair in Forensic Study

Hair, as many people are prone to believe has a role much more than simple beautification. While it provides protection from the elements of course, hair also is a first class tell-tale source for disorders and nutritional imbalances.

In addition, hair is an excellent diagnostic tool to find out possible causes of death especially if caused under unusual and suspicious circumstances.
Hair helps in forensic examination in the following ways
1) In Identification of the victim
• Identification of sex—Sex is determined by the appearance and distribution of the chest hair, beard and moustache and by detection of sex chromatic and Y chromosome in cells of the hair root.
• Estimation of age—Age is estimated by the length, colour and location of hair. Length of the scalp hair in a full term infant is about 3 am. Growth of the pubic and axillary hair occurs at puberty and old people have greying hair.
• Recognition of race—Texture, colour and arrangement of hair differs from one race to the other.
• Genetic traits—Examination of genetic markers is possible from nucleated cells in the root sheath.

2) In Identifying the suspected assailant
This is done by comparing hair present at the scene of crime or in the hand of the victim with the hair of the suspected assailant. In case of rape, the assailant may have on his private parts some hair belonging to the victim.

3) In Identifying the weapon used in crime
This can be determined in the following ways
• By observing the manner in which hair is cut or crushed
• By observing the hair present on a particular instrument with the victim’s hair
• By examining a particular vehicle for victim’s hair in the case of hit and run accidents.

4) In determining whether a particular wound is an incised wound or a crushed wound depending on whether the hair is sharply cut or crushed.

5) In determining the type of burn suffered by the victim : dry burns (singed hair with clubbing),
Scalds (wet hair) and corrosive burns (wet and eaten up hair)

6) In analysing injuries caused by fire-arms and estimating the distance of firing on the basis of singed hair and powder marks.

7) In determining the poisoning and its chronicity by checking for presence of chemicals in the hair. Like heavy metals, poisons are deposited in the hair, starting from the root and extending to the tip. Chemical analysis of the hair not only help in identifying the type of poison but also in estimating the time of exposure on the basis of the fact that hair fibres grow 0.4mm each day.

8) In determining the time of crime by examination of the hair tip. The angle is acute when hair is recently cut, the end rounded after few days and then end tapering after two weeks.

9) In determining whether hair has been pulled out by force. Hair that has fallen by itself will have a degenerated root and hair that has been pulled out by force will have healthy root with a ruptured sheath.