Trace evidence can be thought of as everyday materials of any type occurring in sizes so small that it can be transferred or exchanged between two surfaces without being noticed. Physical evidence often can be found when crimes such as hit-and-run, burglary, arson, robbery, homicide, sexual assault and criminal damage to property are committed. The Trace Evidence Section examines a broad range of microscopic evidence such as hairs, fibers, tape and paint that are left at crime scenes or found on individuals; A broad spectrum of physical evidence including paint, fibers, fire debris, lamp filaments, plastics, lubricants, household and industrial chemicals, cosmetics, tapes, ropes and cordage are all part of what the forensic scientists in the Trace Chemistry Section examine.. The I-MCFSA trace chemists also perform lamp filament on-off determination and the analysis of unknown materials.
The I-MCFSA trace chemists also perform lamp filament on-off determination and the analysis of unknown materials.
Hairs collected at the scene of the crime can provide investigative information about the donor when trying to develop a suspect in a case. The average person naturally sheds about 100 hairs a day, which makes it possible that the perpetrator's hair will be found at a crime scene or transferred onto the clothing of the victim. Hair can be transferred from pubic area to pubic area during sexual assaults, or it can be forcibly removed during a struggle. With a microscope and strict scrutiny, a hair can reveal details about its origin. Examination can reveal whether the hair is animal or human. If the hair is of human origin, the race of the donor and the area of the body from which it originated may be determined.
Fiber and textile evidence can provide strong evidence of an association in criminal cases. The individual microscopic fibers that comprise the variety of textile materials in the world can be transferred from person to person and place to place.
Paint evidence occurs as transfers in a variety of crimes, including homicides, vehicular hit- and-runs, sexual assaults, and burglaries. Paint examinations involve either the development of information to aid an investigator or a comparison between a questioned paint sample from a crime scene and a suspected known source of paint. If asked to perform a comparison, the forensic paint examiner will use a variety of microscopical and sophisticated instrumental techniques to reach a conclusion as to whether or not the questioned sample could have come from the suspected object.