The Seven S'S of Crime-Scene Investigation Securing the Scene. Separating the Witnesses. Scanning the Scene. Seeing the Scene. Sketching the Scene. Searching for Evidence. Securing and Collecting Evidence.

The role of trace evidence in forensic science is to provide links between: The victim and suspect. The victim and scene. The suspect and scene.

If evidence is not properly preserved and stored prior to forensic analysis or testing, it may deteriorate, destroying or devaluing it as a source of information. Those responsible for collecting evidence must understand and employ a variety of evidence preservation protocols, depending on the type of evidence.

Physical evidence is useful (1) to determine how a crime was committed, (2) to connect a suspect with the crime or identify the criminal, or (3) to clear an innocent person.

Traditional forensic analysis methods include the following: Chromatography, spectroscopy, hair and fiber analysis, and serology (such as DNA examination)

Evidence is used to back up or refute arguments, and it helps us to make decisions at work. Using evidence allows us to work out what is effective and what is not.

It provides a permanent record of the crime scene as it was when it was discovered and thus helps remind officers and witnesses of important details that would otherwise be forgotten. Documentation such as this also records evidence that might later be lost, stolen, or destroyed during recovery or transportation.