Hair Analysis In Forensic Science

Being a forensic scientist, with experience of over 20 years in the field, I’ve developed an expert level knowledge of topics such as hair analysis. I routinely classify and perform tests on specific pieces of evidence lifted from a crime scene. After analyzing the data, a forensic analyst, such as myself, will then prepare a detailed report that documents the work that was performed and the findings of the procedures. The integrity of these reports are remained due to the strict adherence to laboratory rules.
In regards to hair analysis, it must be presented along other evidence, as it is class evidence. Therefore, a person can not be indicted solely on hair analysis due to it being circumstantial evidence. When analyzing it, the areas

that are to be compared are the cortex, the medulla, the cuticle. Analysis of the cortex and medulla can be done under a low magnification on a light microscope, while the cuticle must be examined under a high magnification. The cortex of a hair is located between the hair cuticle and medulla and is the thickest hair layer. It also contains most of the hair's pigment, giving the hair its color. Hair has color due to it containing melanin, which is what gives skin its color as well. Evidence can be seen in whether a person has dyed their hair in this layer when under a microscope. The medulla is the innermost layer of the hair shaft and can have patterns such as continuous, interrupted, fragmented, solid, or none. With each pattern, a person’s hair becomes more distinct to them. The cuticle is most commonly imbricate for humans. When examining a hair, the breakage of it indicates the manner in which it was left behind at the scene.

The hair presented is class evidence due to it not providing an individual identification. All brown human hair has the same class characteristics, under a microscope. Their medullas are fragmented or absent and the color and scale pattern of the hair found on any individual varies over their entire scalp. Therefore, a positive identification can not be made simply off of a hair. For this reason, the suspect cannot be identified as the person who committed the crime due to there being a shadow of a doubt. Since the hair being analyzed might not have even come from the suspect, there is not a way this crime can be pinned on them. Locard’s exchange principle is still relevant in this situation and the area the crime was committed has a high traffic volume, therefore, a hair might have been left behind. However, the hair alone is not sufficient enough to identify a person who committed the crime.
It was found that the hair presented did not match the suspect. Through my expert analysis, the patterns of the medulla were not compatible and the color was not close enough to the suspect’s. While the cuticle pattern matched, the texture of the hair did not. While the presented hair was coarse and damaged, the suspect’s hair is fine and in tact. Therefore, in my expert opinion, the suspect cannot be positively identified as the perpetrator in this crime.