14.7: Chain of Custody

Your author will close this chapter with a few words regarding chain of custody. As you may know, chain of custody is the chronological documentation of the movement and possession of an item of evidence from the time it was discovered and collected to the time it is presented in court. In other words, who had possession of the item of evidence, for how long, and for what purpose. Quite often, the ‘for what purpose’ gets overlooked, and a ‘break’ in the chain occurs which might have significant impact to the subsequent investigation or courtroom proceedings. By example, a police officer finds a handgun during a cursory pat search of a suspect. The proper chain of custody for the weapon would be as such: The officer who found the weapon maintains sole possession of the weapon and processes it into evidence and thus begins the chain of custody. The forensic analyst requests the weapon from the evidence custodian in a process that documents the request and release of the weapon. The technician conducts an analysis of the weapon, which might include photographic documentation for disciplinary or courtroom purposes, swabbing the item for DNA-typing, and fingerprint development. The technician then returns the item to documented evidence storage and writes a detailed report. Developed or collected specimen from the weapon is documented and sent off to a laboratory for subsequent analysis, comparison, or typing. The weapon itself is retained by the evidence custodian until it is presented in court proceedings. For this example, let us assume that an additional DNA profile is developed from the collected specimen swab, but the second profile, which did not match the suspect, was not found in the DNA database. This would present a sizeable concern for the prosecution. Let us then imagine another series of events that was never documented in the chain of custody. The police officer discovered the weapon and contacted their supervisor. That supervisor sends another officer to the scene to “borrow” the weapon and bring it to the supervisor’s office for inspection. The weapon is retrieved, brought before the supervisor who examines it and instructs the retrieving officer to put it on a desk to take a photograph. The weapon was then returned to the original officer with the instructions to process it into evidence. All of this was done without documentation, and the original officer’s report reflected only that he had ‘retained possession of the weapon.’ Sadly, this story is not fictitious. This second profile likely belonged to the second officer, the supervisor, or may have been transferred from the desk. You can imagine the impact of this second profile on subsequent court proceedings.