Crime scenes contain the forensic evidence required to apprehend dangerous criminals. The proper collection and processing of physical evidence is of primary importance to most police investigations. Evidence can not only establish the fact of the offense and identify the perpetrator, it may even lead to a conviction. Unfortunately though, poorly conducted crime scene investigations can sometimes either destroy evidence or render it useless.
The primary responsibilities of the initial responder to a crime include the following: (1) to preserve life; and (2) to control suspects and witnesses. Once these two objectives have been achieved, the initial responder should focus their attention on protecting the crime scene. The importance of preserving the scene and its adjacent areas in their original condition cannot be overemphasized. The alteration of a crime scene can cause investigators to draw erroneous conclusions. By expeditiously carrying out his responsibilities, the initial responder may determine the ultimate outcome of an entire investigation.
It is usually the uniformed peace officer who first arrives at the scene of a crime. Protecting the evidence typically involves the establishing a perimeter. In fact, for some crime scenes, two perimeters may be appropriate (Garrison, 1994, pp. 18-20). Only the investigator in charge--and those personnel that he gives permission to--should be allowed to cross these boundaries (Dienstein, 1962, pp. 16-26).
Detectives and supervisors are normally in charge of investigations. There should, however, only be one person in charge of the crime scene itself. The first question that the investigator will ask when he arrives is as follows: "Has anyone been allowed to enter the scene" (Dienstein, 1962, pp. 16-26)? The investigator should then use whatever resources are available (e.g., barricades or other uniformed officers) to further protect the area. Such measure...