Plastics and Polymers

Materials such as duct tape, vehicle lenses, trim tape, rubber or anything that is made from plastic can be submitted to the Trace Evidence section for comparison. The techniques used to examine and compare these materials are the same as those used for paints and coatings. However, as with all trace materials, the examiner must have a good understanding of the materials, how they are produced and what variation exists among the products. Vehicle year, make and model information can also be developed from vehicle parts left at a crime scene. A related area of examination includes the comparison of the striations noted on plastic bags. These stria are formed from the manufacturing process and often provide the potential for determining whether or not questioned and known bags were manufactured on the same machine.