Hair and Fiber Analysis

Hair and Fiber Analysis

Prior to beginning this activity, please review the required resources:

Watch:

Read:  I have already read through the following sources some and paraphrased further down in the document.

Your paper should address the following elements:

  • Explain which scientific techniques would be used for biological and non-biological evidence such as hair and fiber both at a crime scene and later in the lab. Cite examples.
  • Evaluate how hair and fiber analysis might contribute to the investigation and any subsequent court proceedings.
  • Explain how forensic scientific techniques related to hair and fiber analysis has evolved throughout history.

The Hair and Fiber Analysis paper  

  • Must be approximately 1,000 words (approximately four double-spaced pages in length, not including title and references pages) and formatted according to APA style as outlined in the Writing Center (Links to an external site.).
  • Must include a separate title page with the following:
    • Title of paper
    • Student’s name
    • Course name and number
    • Instructor’s name
    • Date submitted
  • Must use at least two scholarly, peer reviewed, and/or other credible sources in addition to the required resources.
  • Must document all sources in APA style as outlined in the Writing Center.
  • Must include a separate references page that is formatted according to APA style as outlined in the Writing Center.

References already read through and paraphrased…

There can be many types of evidence present at crime scenes. From biological body fluid evidence to fingerprints and soil, each type of evidence requires different collection and preservation techniques.

HAIR EVIDENCE

Schade, T. (2016) How to collect hair and fiber evidence at a crime scene [Video file]. National Forensic Academy. Retrieved from https://youtu.be/cfWsgS0ID-s

The oblique lighting technique is a commonly used method due to the need of retrieving only the most recent deposits of hair and fibers. This is used instead of the traditional vacuuming technique that would collect more unnecessary particles. There are various different ways to collect hair and fiber evidence. Two of the most common techniques are putting the evidence in paper with a pharmacy fold after it is collected with either forceps or a gloved hand or using the sticky strip on a sticky note to pick up the hair or fiber evidence.

DUTELLE 2016

The primary paper envelope used should be placed inside a second envelope with all corners secured.

Deedrick, D. (2000, July). Hairs, fibers, crime and evidence; Part 1: Hair evidence. Forensic Science Communications 2(3). Federal Bureau of Investigation. Retrieved from https://archives.fbi.gov/archives/about-us/lab/forensic-science-communications/fsc/july2000/deedric1.htm

Once hair evidence arrives at the forensic laboratory, the most common method of testing and evaluation is by using microscopy. The first step in this process is to identify unknown hairs and then compare them to a sample of known hair. The comparison microscope is used for this examination due to the fact that the comparison microscope consists of two compound microscopes that are connected via an optical bridge, allowing the view of the hairs to be presented side-by-side against one another for easier comparison.

First, the hair evidence is evaluated for physical characteristics. Among the characteristics noted are whether the hair evidence originates from an animal or human. If determined to be human hair, the next step is to determine the body part that the hair originated from. Hair from different parts of the body has certain distinguishing characteristics. After the body part of origin is determined, the examiner can continue the analysis by determining the particular racial group the hair belongs to as each racial group has distinguishing hair characteristics. From there the examiner can also attempt to determine age and sex of the individual from which the hair originated. Using microscopic examination and detective work, it is possible that an individual can be found and a sample taken to compare the analyzed hair with in order to make a positive identification.

DUTELLE, 2016

Hair evidence can also be evaluated in order to retrieve a DNA profile from it. If it is beneficial to the case, DNA may be collected or pulled from the root of the hair. Once collected and analyzed, the DNA can be compared to a blood sample from a known individual.

ANALYSIS OF FIBER EVIDENCE

Deedrick, D. (2000, July). Hairs, fibers, crime and evidence; Part 2: Fiber evidence Forensic Science Communications 2(3). Federal Bureau of Investigation. Retrieved from https://archives.fbi.gov/archives/about-us/lab/forensic-science-communications/fsc/july2000/deedric3.htm

Once the fiber evidence arrives at the laboratory, much like hair evidence, it is analyzed via comparison microscopy. The fiber can also be analyzed using chemical analysis. The more unique fiber evidence is, the easier or harder the process could be in making a positive, matching identification.