Hair and Fiber Analysis

  History of Hair/fiber analysis


 In the early stages of forensic science the significance and value of examining hair during a criminal investigation was realized. Published in France in 1857, one of the first scientific reports regarding trichology, the scientific study of hair, introduced the world to the idea. The field expanded rapidly after microscopic hair examination became known in the early 20th century. Professor John Glaister's "Hairs of Mammalia from the Medico-legal Aspect," published in 1931, became a renowned resource for hair analysis information and in 1977, John Hick's "Microscopy of Hairs


Major types of fibers
Personal Reflection

We had to anaysis many types hair and fibers like Asian, dog, cat, black girl, cotton, nylon, and silk hair and fiber. We looked for if the hair was cut or split and if it had any specail characterstics.

·        Angora

There are two types of Angora:

Mohair (made from the Angora goat)

Angora Rabbit Hair (made from the Angora rabbit)

·        Yarns

Yarns made from the fibers of these animals are very soft, lustrous, lightweight and warm. Alpaca is often used for the manufacture of warm, luxurious apparel.

·        Cashmere

Cashmere, also known as the fiber of kings, is produced from the fine, soft undercoat of hair of the Kashmir goat. Sixty percent of the world's supply of cashmere is produced in China, Mongolia and Tibet, and the remainder from Turkey, Afghanistan, Iraq, Iran, Kashmere, Australia and New Zealand. Cashmere yarn is extremely soft, lightweight, yet very warm.

·        Wool

Wool is a natural fiber made from the fleece of sheep. Talk about wool and it conjures up a picture of cozy warmth. However, wool is not uniform among all sheep. Sheep live in a wide variety of climates and conditions, and develop their wool to suit the conditions under which they live or are bred.

·      Silk

Silk is a natural protein fiber containing about 70-75% of actual fiber fibroin secreted from two salivary glands in the head of the silkworm larva, and about 25-30% serein, a gum which cements the two filaments together. Silk of the finest quality is obtained from the unwound filament of the silkworm cocoon. To obtain lower grades of silk, broken or waste filaments and damaged cocoons are retained, treated to remove the serein, and combed.   

             Hair/Fiber collection techniques came and the part of the body from which it originated. Human hair can be compared to determine whether or not two samples could have had a common origin. The value of the Laboratory examinations of such specimens will depend upon the amount of hair recovered and the characteristics found in the examinations. Recover all hair present. If possible, use the fingers or tweezers to pick up hair, place in paper bindles or coin envelopes which should then be folded and sealed in larger envelopes. Label the outer sealed envelope. If hair is attached, such as in dry blood, or caught in metal or a crack of glass, do not attempt to remove it but rather leave hair intact on the object. If the object is small, mark it, wrap it, and seal it in an envelope. If the object is large, wrap the area containing the hair in paper to prevent loss of hairs during shipment.

Typical Hair/fiber analysis

      By identifying and comparing animal and human hairs under a microscope, investigators gain valuable insight into events that occurred at a crime scene. By analyzing this information, they can establish physical contact between suspect, victim and crime scene and use the information in court to aid in the prosecution or defense. Further bolstering the validity of such evidence, DNA technologies have become equally important in forensic hair analysis. According to Lee Lerner's article "Hair Analysis," by combining DNA testing with microscope procedures, investigators can now screen for illegal drugs, test for presence of heavy metals, test for nutritional deficiencies and discover the approximate age of a person all by analyzing a single strand of hair.

     Reliability of Hair/fiber crime scene data

The investigation and successful prosecution of individuals suspected of involvement in violent crimes often includes the identification and comparison of trace evidence. Deedrick says hair evidence is only of value when used in conjunction with other evidence. Although forensic hair analysis does serve as permissible evidence in court, it does not necessarily serve as incontrovertible proof because in general, a hair comparison does not mean complete recognition of an individual's identity. The FBI publication "Forensic Science Communications" says that by providing many associations and many cross matches conducted by several examiners, the validity of hair analysis evidence approaches 100 percent. The professionalism and experience of the examiner as well as the methods used in analysis will factor into the validity of any result obtained from hair fiber analysis.

Notable or famous case where hair/fibers were used to convict or exonerate a suspect.

·        Atlanta Murders (1979-1981)

Over a two-year period, 29 young African Americans were found strangled and smothered in Atlanta, Ga. Eventually, a police stakeout identified a suspect, Wayne Williams, who had a suspicious explanation for why he was on a bridge not far from where a body was found two days later. Lacking witnesses, forensic investigators built a case against Williams that was based almost entirely upon fiber and statistical evidence. Working with chemists from textile maker DuPont, they linked a fiber found in one victim’s hair to an unusual make of carpet in Williams' home, and calculated that the odds of the victim coming in contact with it in the Atlanta area were 1 in 7,792. A fragment of rayon found on another victim’s shorts was consistent with the carpeting in Williams’ station wagon, a match that had a 1-in-3,828 chance of occurring in Atlanta. Either piece of evidence left room for reasonable doubt, but the probability of both happening by coincidence was 1 in 29,827,776. Fiber evidence from other victims drove the odds up into the trillions. It took a jury less than 12 hours of deliberation to find Williams guilty, and he is now serving two life terms.