Get Hair Fiber Evidence Assignment

Hair is considered class evidence and is useful in backing up other circumstantial evidence, such as by placing someone at the crime scene.

Nuclear DNA analysis can be done on human hairs. The trace section assists the DNA section by screening hairs and determining their suitability for DNA testing. A microscope is used to examine the root end of the hairs, in order to determine if they are suitable.

Because hairs can be transferred during physical contact, their presence can associate a suspect to a victim or a suspect/victim to a crime scene. The types of hair recovered and the condition and number of hairs found all impact on their value as evidence in a criminal investigation.

To collect pulled hairs, be sure to wear new, unused, clean latex or nitrile gloves and pull 25 hairs (or have the suspect or person of interest do it themselves) from various areas of the scalp or pubic region. Place these in an evidence or pharmacy fold, place the fold in an envelope and properly label.

Hair is a valuable tool for forensic scientists. It is more resistant to decay than most other body tissues and fluids, thus remaining intact far longer than other evidence. This durability makes hair one of the most frequently found pieces of evidence at crime scenes.

The hair shaft (main part of the hair) is considered class evidence but if the root is intact and DNA can be collected then it is individual evidence. Because most hair collected is class evidence, it is not possible to prove that it came from a particular person.

The examination of fiber and hair evidence is usually comparative. It can associate persons, places, and objects. Individual fibers cannot be 'matched' to a single source. However, a torn or cut piece of fabric may be physically fit (as a jigsaw) to another piece of fabric, thereby making a definitive association.