READ: Collecting and Packaging Evidence

Chain of Custody

In addition to being properly labeled, the chain of custody must be maintained for each piece of evidence. The chain of custody is a record of all personnel who had possession of a piece of evidence. Every time evidence is transferred from one person to another the transfer must be documented. There is a log on the evidence packaging, or a log that is kept with the evidence to document every person that had the evidence at all times. The person who transferred the evidence and who they gave it to, along with the date and time, must be recorded every time evidence is transferred. Maintaining the chain of custody is important so that when a piece of evidence is used in court, there is no question about where the evidence has been since it was taken from the scene. The chain of custody helps to prove that the piece of evidence was the same exact piece of evidence that was taken from the scene. If there is any question about this the evidence may not be allowed to be used in the case.

An example of how the chain of custody works is described below:

Officer Miranda Johnson finds a jar of white powder at a scene. She packages it and records her name as the person who recovered the evidence. She records the time the evidence was found. She then takes it to a lab and gives it to the lab technician, Derek Harris. Derek will test the powder to determine what it is. Derek will put his name on the log with the date and time of transfer. When Derek is done with his testing he puts the evidence back in the package and gives it to lab manager Susan Blake. Susan puts her name on the log with the date and time and stores the evidence in a secure locker until it is needed.

If there is any debate in court about whether the powder that was tested was the same powder at the scene, the chain of custody helps prove that everyone involved kept track of the exact powder from the scene. The chain of custody accounts for where the powder was at all times. It is best to keep the transfers of evidence to a minimum so that the chain of custody is clear. The fewer the people who handle the evidence, the better.