Investigation of Biological Evidence

The investigation of crime is in fact a dynamic process of formulation and testing of the hypothesis of crime and there is no substitute for a careful and thoughtful approach. An investigator must not jump to hasty conclusions as to what happened based upon limited information but must generate several different theories of the crime, keeping the ones that are not eliminated by incoming information at the scene. Physical evidence can range from massive objects to microscopic items, resulting from a crime and recovered at the scene or relevant locations. The purpose of the observation and documentation of the crime scene condition is to note the location of potential evidence and to mentally outline how the scene will be examined. Considering all sources of information available in investigations, physical evidence plays a vital role. Physical evidence, when recognized and properly handled, offers the best prospect for providing objective and reliable information regarding the incident under investigation. However, the value of even the most carefully recovered and preserved evidence can be lost if the chain of custody is not properly maintained. Chain of custody exists to ensure full transparency in the process of how evidence is collected, handled, and stored. Once an item is recognized for its evidence value, the collection becomes a relatively simple matter of performing the following routine tasks; i.e., handling the evidence properly, marking the evidence for later recognition, packaging the evidence to prevent alteration or damage, tagging the evidence for package recognition, and maintaining the chain of custody. The last phase of the crime scene investigation process aims at selecting the means of transportation and storage that are appropriate for the type of physical evidence to ensure the integrity of evidence to be forwarded to the laboratory. In a broader sense, crime scene management— implementing new technologies and methodologies in forensic science—is the first and most important golden moment in solving any crime and strengthening the criminal justice system.