Paint evidence is found in the majority of hit-and-run cases, and it may provide a link between a victim and the responsible vehicle. Paint evidence may also be present in various other types of crimes, including burglary and homicide cases. Paint may be left as chips or smears on clothing, vehicles, or objects, or loose at the scene. Additionally, cross transfers of paint between two vehicles, a vehicle and an object, or two objects may occur.
Paint as evidence falls into two main categories just as any other type of evidence does. Paint can simply indicate the “class” from which it comes. This could mean differentiating between automobile paint, house paint, nail polish and other types of paint. This is usually done through very detailed chemical analysis of the various layers of paint and physical examination of paint samples. Although various manufacturers may use the same supplier of paint the layers and colors may vary from manufacturer to manufacturer.
Paint can also indicate individual characteristics. This is only truly possible when there is an exact match of the edges of two paint chips. However, when the physical properties such as the color and number of layers and the chemical and biological profiles show multiple points of similarity with reference sample the probability of a common source increases.
All paint samples that are left at a scene should be collected. Additional evidence may also be present and should be collected. Examples of such evidence are automotive parts, glass, and plastic lens pieces at a hit-and-run, or plaster, wood, and safe insulation at a breaking and entering.
Paint may transfer to the clothing of a hit-and-run victim, perpetrator of a burglary, or other person involved in an incident. Paint evidence on clothing may be present as chips or smears. The size of the chips or smears may range from large and visible to microscopic and invisible to the naked eye. Loose, visible chips that are easily handled may be removed and packaged separately in appropriate containers that avoid breakage of the chips. If the article of clothing is damp, it should be air dried and packaged to minimize loss of the paint evidence. For example, individually wrap the clothing items in butcher paper and place the butcher paper package into a paper bag. Do not excessively handle the evidence.