IDENTIFICATION FROM HAIR
Different medico-legal questions which may arise in connection with hair are related to identification of a person and other medico legal aspects. To enumerate them,
Details on medico-legal aspects of hair:
Hair may very occasionally be confused with some other fibre, vegetable origin like, cotton or jute fibres, semi synthetic fibres like those manufactured from cellulose or purely synthetic fibres like nylon, polyvinyl or polyester fibres. Natural fibres can be known by naked eye and microscopic examination. For synthetic fibres, to know their exact nature, certain other tests are necessary. Human and animal hair have distinct morphological features which are discussed after description of other fibres.
Description of fibres -
COTTON FIBERS are flattened and twisted. Microscopically they have long tubular cells.
JUTE fibres are smooth fibres with irregular cell cavities.
SILK fibres are fine, long filaments having no cells in them.
SYNTHETIC FIBRES are non-cellular fibres of varying thickness, elasticity, contractibility, density, solubility and chemical composition. To differentiate them from one another, tests for these properties are performed.
The difference between human and animal hair can be drawn on the following points:
In MALES, the hair is comparatively
thick or coarse. Scalp hair is comparatively shorter. Facial hair and hair on other parts of the body namely chest and limbs, are abundant and distribution of pubic hair has upward extension with the apex near the umbilicus. Microscopically, Barr bodies are very rare in the cells of the hair bulb.
In FEMALES, the hair is comparatively thin or delicate. Scalp hair is comparatively longer. Distribution of hair is usually limited in the scalp, axilla and pubic regions. Distribution of pubic hair is limited in a transverse straight line, a short distance above the mons veneris. Microscopically, Barr bodies are comparatively more common in the cells of the hair bulb.
When bleached, hair appears pale or colourless and when dyed it takes the colour of the dye. Grey hair is usually dyed with black dye. In some community hair is beached and then dyed with ‘mehendy’ to give a reddish brown colour to the hair. When dyed, the time passed after dyeing can roughly be calculated out from the length of the hair near the root which has grown after dyeing of the hair and does not show the presence of the dye. Chemical analysis of the dye used can also help to identify an unknown person or dead body.
If hair bulb is present then, the blood group of the person can be determined by “absorption-elution technique” or mixed agglutination technique.
Occupation of a person can be guessed form the hair if trace elements can be detected from his hair, by using modern scientific investigation processes including neutron activation analysis, if the hair of the person is or was vulnerable to be contaminated in course of his occupation with the trace elements to be detected in his hair. In occupations, where the person is exposed to substance like arsenic, the same may be detected in his hair. In aniline industries, the hair of the workers may have a bluish tinge and in copper industry it may have greenish tinge. In miners and some other industrial workers, there may be early baldness. In some industries, hair of the workers may become brittle and lustreless.
Trace elements as discussed in A6 above will help identification of the person. Trace evidences like blood or semen may help to identify the assailant or the rapist by grouping test of the blood or semen present.
If the sample hair is studied against the hair of the accused or victim on all the points discussed in above paragraphs, then it can be said whether the sample hair belonged to the accused or the victim.
This can be determined form the length, shape, texture and some other features of the hair.
Scalp hair is long, straight or wavy or curly and medium in texture in Indians. In males, the tip may be flat if the subject had recent hair cut. In cross section, the cut surface is circular or oval or plano-convex, depending on whether the hair is straight, wavy or curly.
Beards and moustaches are short in length (length may be up to 3” for moustaches and 10” for beards), wavy or curly, thick or course and tip may be flat, if recently shaved. In cross section, the cut surface is plano-convex or triangular.
Eyebrows and eyelashes are short, curved, thick and taper to the tip. In cross section, the cut surface is plano-convex or triangular.
Axillary hair is short, straight or curly, thick or coarse and the tip may be splitted or frayed. Cut sections have nothing in specific.
Pubic hair is short, curly, and thick with splitted or frayed tip. Cut section has oval or triangular surface.
Nasal hair is very thick, short, curved with triangular cut surface.
Hair on other parts of the body is short, curved, and thick with triangular cur surface.
The body part to which the hair belonged, is important, to know, whether it was a case of assault on the head or a case of sex assault viz. rape or sodomy.
A hair taken out forcibly, will have a full roundish hair bulb covered with a torn sheath. A hair fallen off naturally, will have no bulb and sheath at its root end. If the hair has been taken out forcibly, that indicates fight or struggle.
If a female pubic hair is detected on the glands of the accused of a case of rape or if a male pubic hair is available near the private parts of the victim of a case of rape, then relationship between the offence, offender and victim can be established by studying the sample hair recovered from the male or female genitalia and the pubic hair of the victim or the accused. Similar is the position in sodomy cases (pubic hair of the active agent and anal hair of the passive agent) and bestiality cases (pubic hair of the accused found near the anus or vagina of the animal and the animal hair near the private parts of the accused). If it is a case of mechanical assault, then hair may be present in the weapon recovered from the possession of the accused, which may be compared with the hair of the victim to establish relationship between the offence, accused, victim and the weapon of offence.
In death due to head injury, the hair of the affected part of the head may be crushed or may show sharp cutting, depending on whether hard, blunt or sharp cutting weapon was used. In death due to arsenic poisoning, the poison may be detected in the hair.
In case of lacerated injury over head, the hair bulb is crushed. In case of incised or stab wound, the hair is sharply cut.
In case of head injury, if the hair bulbs are crushed then it can be said that hard, blunt weapon has been used. If there is sharp cut on the hair, then a sharp cutting weapon must have been used.
In homicidal cases the hair of the assailant may be held in tight grip of the hand of the victim in a state of cadaveric spasm, as a result of struggle before death.
In chronic arsenic poisoning, when the patient is still surviving, hair serves as good material for detection of the poison and diagnosis of the case.
In burning cases the hair get singed. Singeing of hair, of course, does not specifically indicate ante-mortem or postmortem nature of the burning. It is a point to differentiate between ulcers due to burn, scald or chemical agent. In fire-arm injury cases, singeing of the hair around the wound indicates about the short distance of the firing. If hair around the wound is singed, then muzzle end of the weapon was within a distance from which the fire from the muzzle end could travel up to the body of the victim at the time of the firing.
In case of death of a male subject, if the date and hour of his last shave is known (e.g. from the fixed barber), then from the length of the beards and moustaches, or beards alone, it can be said, for what period the deceased survived after his last shave. This identity gives the time of death. (Rate of growth of
See column A6 and A7 above.
Hair resist putrefaction and thus can help to identify the deceased and at times can help to know the cause of death (see Col. B4.), even years after death when hair and/or bones may be the only available remains of the dead body.