ABSTRACT

Impression evidence is categorized in two major categories, two-dimensional impression evidence and three-dimensional impression evidence. Tool marks are three-dimensional impressions that result when a hard object comes into contact with a softer substance. For an investigator the three-dimensional prints should be fairly obvious on initial inspection of likely areas in the scene. Two-dimensional impressions, or dust prints, occur when the dust or contaminants on a suspect's footwear or tire are transferred to the surface being walked upon. They may also be present on the clothing or body of the victim when a stomping occurs. The use of powerful oblique lighting by the investigator will greatly assist in locating two-dimensional impressions. Two-dimensional moisture impressions occur when the impressing surface moves something wet and then comes in contact with a dry, firm surface. Hard outdoor surfaces contains two-dimensional impressions. These may need to be processed quickly by the investigator to avoid loss due to environmental factors.