How Crime Scene Evidence is Collected

When crime scene investigators arrive on the scene of a crime they must take every precaution to leave the scene undisturbed and collect evidence in a thorough and careful manner.

In order to ensure evidence is collected in such a way as to preserve it for analysis, CSI professionals should follow various protocols for evidence collection. And because different crime scenes have different characteristics, such as the amount of time which has passed since the crime was committed, CSI professionals must be sure to take the utmost care when processing it. Here we will take a look at some evidence collection protocols for different kinds of evidence.

When collecting hair evidence CSI agents are recommended to use tweezers or gloved hands and collect all hair found on the scene. The hair should then be placed in envelopes, labeled, and then stored for further processing.

Hair which is caught in another object, such as a splinter in a door, may be better left embedded in the object and processed later.

Blood can be soaked up by a sterile cloth such as gauze and then allowed to air dry at room temperature. Blood should be refrigerated or frozen as quickly as possible and taken to the processing center immediately. The quality of a blood sample can degrade quickly so it is important to prevent it from becoming contaminated with other fluids or being exposed to high temperatures.

Seminal stains may be found in various areas including on the victim’s body, on floors, beds or sheets, and other areas of the crime scene. The sample should be allowed to air dry and should be packaged in a paper bag. It is not recommended that seminal stains be stored in plastic bags due to the possibility of contamination.