ABSTRACT
The more physical evidence recovered, the more likely a functional and objective theory of what transpired during the crime will be forthcoming. Before the crime scene technician can expect to process a scene for evidence, she or he must have a working knowledge of the nature of physical evidence, what a crime lab can do with it, and how best to collect it. This in no way presupposes that they are experts in every discipline of forensics; lacking this understanding, the technician is likely to overlook evidence or collect it in an inappropriate fashion. Based on specificity, the characteristics presented by all physical evidence can be classified in two categories: class characteristics or individual characteristics. Class characteristics describe traits or characteristics of evidence that allow the item to be compared with a group. Individual characteristics allow the forensic scientist to compare the item with a specific object or person and include or exclude it as having originated from it.
