Trace Evidence
Looking for trace evidence at a crime scene is very important, as there is much that it can tell an investigator. This kind of evidence can provide information about the time of death, who might have committed the crime, and the sequence of events which took place and led up to the crime, as well as what may have happened after the crime had been committed (i.e. was the victim killed there, or moved from somewhere else after death?). One of the best types of trace evidence from the standpoint of solving the crime is blood (Penrod, 2003). This can provide a lot of DNA evidence, and it can also tell a lot about the crime itself. How much blood is left in a human body is important, but so are trace amounts of blood in other places, such as in a car or on the clothing of a suspect. In addition, blood found on an alleged murder weapon can also help investigators piece a crime together and work at solving it. Because of this, there are specific ways to collect trace evidence (Penrod, 2003). Gloves should always be worn to avoid contamination of the crime scene. It is possible that other people have already been through there and touched things, and those people must be eliminated as suspects. Avoiding further contamination, however, is vital to ensuring that the crime has the highest chance of being solved. In addition to wearing gloves, collecting evidence at a crime scene also involves making sure that the evidence, once collected, remains free from any contamination (Penrod, 2003). There are specialized containers which are used to collect certain types of evidence from crime scenes. Other evidence, such as hair or fibers, is usually just placed in a clean, dry baggie and sealed up. It is very important at that point that where the evidence came from and who collected it is documented. Any time it changes hands, that must also be documented. This can help to ensure that it can be used as evidence at trial, because there is allegedly no chance that it has been tampered with in any way (Penrod, 2003).
Bibliography
Penrod, S. 2003 Eyewitness identification evidence: How well are witnesses and police performing? Criminal Justice 18(1): 36-47.
