Forensic Laboratory Services

Chemistry

Physical evidence routinely examined includes: paint, fire debris, clothing and footwear, glass, fibres and textiles, safe insulation, and a wide range of commercial products. The examination of exhibits may be classified into two categories: the identification of an unknown substance; and the comparison of “known” and “questioned” exhibits. Services include:

• recovering, comparing and identifying non-biological trace evidence (paint, potential fire accelerants, glass, fibres and textiles, plastics,
• building products, safe insulation and commercial products);
• conducting physical matching of the seized materials;
• providing scientific and technical support to other forensic disciplines; and
• hosting and supporting the Paint Data Query (PDQ) database.

A pedestrian was killed in an early morning hit and run collision. The next day an individual drove his vehicle to the police station, alleging that his vehicle had been stolen during the night, then returned to its parking place. He had found his damaged vehicle the next morning. Its windshield was cracked and the driver’s side window was broken. Laboratory examination in the Chemistry section linked this vehicle to the collision because two paint chips recovered from the scene of the hit and run were physically matched to the vehicle. The victim’s shirt also bore paint chips that matched the paint taken from the vehicle. In addition, approximately 40 glass chips were recovered from the victim’s shirt. Of these, six were determined to be non-tempered glass that had the same refractive index as the outer pane of the windshield. In attempting to identify a suspect, it was thought that if the owner of the vehicle had been driving at the time of the accident, then his bed linen might contain glass. A bed sheet and a pillow case were submitted to the Chemistry section. A glass chip was recovered from the pillow case and six glass chips were recovered from the bed sheet. They had the same refractive index as the driver’s side window. In addition, two glass chips recovered from the bed sheet matched the inner pane of windshield glass. The suspect’s jeans bore three glass chips that had the same refractive index as the driver’s side window (one was large enough to identify as tempered) and one glass chip that had the same refractive index as the inner pane of windshield glass. The suspect’s t-shirt bore approximately 50 small (less than 0.25mm x 0.25mm) glass chips. The refractive index of nine of these chips was determined. Each matched the driver’s side window glass. This case was completed with a guilty plea from the owner of the vehicle.

If you are interested in a career as a specialist in the Chemistry Section, you will need to have a Bachelor of Science (honours) degree or equivalent degree in chemistry from a recognized university. A technologist requires a three-year diploma in chemical technology or equivalent. Consult the Careers page for additional employment information.