Hair evidence can be an important element in solving crimes because it can put a victim and suspect together at a crime scene. Hairs can be transferred directly or from one person to another, or through indirect means. An example of indirect transfer would be when people shed hairs onto their clothes and then transfer them to another person.
Clues From Hairs
Forensic scientists can determine a number of things from analyzing hairs found at crime scenes. The clues that hairs reveal include what part of the body the hairs came from, the race of the person they came from, if the hairs shed naturally or were pulled from someone's head, and whether the hairs were color treated.
Kinds of Hair Evidence
Hair evidence can come from all over someone's body, but some hairs are more useful than others. Hairs from the head and genital area yield the most evidence because of their unique nature. Although hairs from the face, chest and underarm can put someone at a crime scene, they are usually not tested by forensic scientists.
Collection of Hairs
When hairs from a suspect's head are needed for analysis against hairs found at a crime scene, they are plucked directly from different areas of the person's head--as well as taken from a comb. Likewise, when pubic hairs are collected from a suspect's body, they are taken from several areas of the pubic region. In both cases, about 25 hairs are collected for testing.
Examination of Hairs
When forensic scientists analyze hairs, they first determine if the hairs came from a human or an animal. If the hairs came from an animal, they then work to identify the species of the animal. If the hairs came from a human, forensic scientists compare the hairs found at a crime scene to the hairs taken from a suspect. This examination will determine if the suspect was indeed at the crime scene.
Importance of Animal Hairs
Although animal hairs found at a crime scene cannot be linked to an individual animal, knowing the species can go a long way toward putting a suspect at the scene of a crime. For example, dog hairs may be found at a crime scene but it is discovered that the victim does not own a dog. If the suspect owns the breed of dog that the hairs came from, this evidence strongly suggests that the suspect and victim had contact.