Chain of Custody
The chain of evidence is a series of connections that draws an investigator from one piece of evidence to another. Chain of evidence is also sometimes used interchangeably with “chain of custody.” The chain of custody is the series of places where a piece of physical evidence has been from the time that it was gathered to the point that it is introduced at trial. Chain of custody must be proved when evidence is not unique or where relevancy depends on its analysis after it was seized.
To prove the chain of custody, the party must show:
- That the evidence is what the party says it is (e.g., a bullet from the crime scene)
- That it has been in constant possession and who has possessed it from the time it was seized to when it was presented in court
- That the evidence remained in the substantially same condition from the time that the person in the chain of custody took possession until the time it was transferred to another person (e.g., that it was in secured storage where only the witness had access to it).
When the chain of custody has been proved, the foundation has been laid for the particular evidence, and it can be presented to the jury. For example, during an investigation, a police officer finds what he believes is about a pound of marijuana in the defendant's handbag. The first officer hands the marijuana to his partner, who delivers the marijuana to a lab, which confirms that the package indeed contains marijuana. The lab technician who tested it gives it to a police detective, who brings the marijuana to court. The testimony of the arresting officer, his partner, the scientist and the police detective would constitute a chain of custody for the marijuana.
Each person would have to testify that the marijuana was in the same condition when they received it and passed it onto the next person in the chain. A chain of custody does not necessarily have to be proven for every piece of physical evidence (e.g., evidence with serial numbers or that which is so unique that it can be assumed the original.) The opposing parties can also stipulate (agree) as to the chain of custody and authenticity of the evidence. Whether the chain of custody has been established is up to the trial judge. Chain of custody matters are complicated legal issues that should be handled by a knowledgeable and experienced criminal defense attorney.