The paint chips, footprints, residues, hairs and other traces left at the scenes of crimes and accidents can be invaluable evidence, but it takes skill to find, preserve and interpret trace evidence.
Trace Evidence Analysis
Although the CSI Effect has made crime scene investigations and forensic laboratory work familiar to the public, the more spectacular DNA profiles are believed by many to be the true forensic science that solves the most cases. Trace evidence analysis is often regarded as an also-ran, even by young forensic scientists.
Paint Samples, Foot and Tire Tracks, Arson Debris
Any evidence recovered from a crime scene that is tangible, like paint samples from a hit-and run accident or skid marks at the scene of a road accident can be regarded as trace evidence. Additionally, foot and tire impressions, explosive and arson debris, and other substances can qualify.
Trace evidence is collected, analyzed, and compared differently depending on the jurisdiction. In large cities, several people might carry the title of Trace Evidence Analyst. In smaller jurisdictions, however, the medical examiner may be responsible for conducting this type of forensic investigation, or maybe even the police. Private Forensic Labs also employ Trace Evidence Analysts.
New York State Division of State Police
According to the New York State Division of State Police, protecting a crime scene from contamination, and gathering and interpreting evidence accurately, have become three of the most critical ingredients in crime solving.
As forensic science develops and matures, advances in technology are being applied to the field of forensic science, “a field in which technical competency is achieved only by the synthesis of a number of factors, including training, experience, supervision, continuing education, proficiency and an appreciation of scientific methods and protocols projected against a background of stringent professional ethics.”
Duties of a Trace Evidence Analyst
At the New York State Division of State Police, the Trace Evidence Analysts help investigate accidents and cases involving arson residue, paint, and glass, especially in road accidents.
Analysts specialize in the following:
- analysis of impressions and dust prints
- explosive residues
- animal hair identification
- human hair characteristics.
Michigan State Police Forensic Science Division
The Trace Evidence Unit is one of the most diverse and unique of all disciplines in the Forensic Science Division (FSD) of the Michigan State Police (MSP). An examiner in this unit will see a wide range of evidence and must be proficient in several areas.
According to their website, a Trace Evidence Analyst at the Michigan State Police Forensic Science Division must possess a bachelor’s degree in chemistry or other natural science with a strong background in microscopy, analytical instrumentation, and photography. An incoming analyst has a very extensive training period under a senior examiner. Each of the above disciplines must be studied, practiced, and mastered before the analyst begins performing their own casework.
In their jurisdiction, the following types of evidence are analyzed by the Trace Evidence Analyst:
- Hairs and Fibers
- Paints (automotive and architectural)
- Explosives
- Glass
- Headlamp Filaments
- Footwear and Tire Impressions
- Physical Matches
- Arson Debris
- Acids/Bases
- Miscellaneous Unknowns
Oklahoma State Bureau of Investigation Forensic Services
Trace Evidence also includes evidence that cannot be seen by the human eye without instrumental assistance. A range or microscopes and other instruments are used by the Trace Evidence Analysts.
The OSBI Trace Evidence Unit analyzes several types of evidence including Fibers, Paint, Gunshot Residue, Ignitable Liquids, and several others. “A Trace Evidence Analyst spends years training in these specified fields. Each sub-discipline takes dedication and hundreds of hours in training in order to become proficient.”
Responsibility of a Trace Evidence Analyst
Road accidents, arson or explosion scenes or crime scenes – trace evidence analysts have a threefold responsibility to ensure that the integrity of the crime scene is protected; the evidence is gathered and then analyzed and interpreted correctly.
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