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Articles » Crime Scene And
Physical Evidence
What is Physical Evidence?
Lawrence Chow
Physical evidence is any object that can establish that a crime has been committed or can provide a link between a crime and its victim or between a crime and its perpetrator. The examination of physical evidence by a forensic investigator is usually undertaken for identification and comparison. The purpose of identification is to determine the physical or chemical identity of a substance with as near absolute certainty as existing analytical techniques will permit. The objective of a comparison is to determine whether or not the suspect specimen and a control specimen have a common origin, by subjecting them to the same examinations and tests. In a comparison analysis, the forensic investigator must not forget the role that probability plays a determining factor in the discovering the origins of two or more specimens. Evidence is said to possess individual characteristics when it can be associated with a common source with an extremely high degree of probability. However, evidence that can be associated only with a group and never with a single source is said to possess class characteristics.
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