What is chain of custody?
Chain of custody refers to the documented handling of physical evidence from the time it is collected through the time it may be presented in court. This can include information about who collected the evidence, where it was stored, who accessed it, and whether it was transferred, tested, or altered along the way.
The purpose is to help establish that an item presented in court is actually the same item that was originally collected and that it has not been improperly substituted or materially changed.
Does a broken chain of custody automatically make evidence inadmissible?
Not necessarily. A problem with the chain of custody does not automatically mean evidence will be excluded.
California courts generally require evidence to be properly authenticated before it can be admitted. For writings and other documentary evidence, California Evidence Code requirements include showing that the item is what the party offering it claims it to be. Supreme Court of California
When physical evidence has gaps in its documented history, the defense may challenge whether the prosecution has adequately established its identity, condition, or reliability.
What kinds of chain-of-custody problems can arise?
Issues can include missing documentation, unexplained periods when the location of evidence is unknown, improper storage, mislabeled evidence, conflicting identification numbers, contamination, or questions about who had access to an item.
These concerns may be especially important in cases involving substances, DNA samples, firearms, biological evidence, electronic devices, or other items that undergo testing or laboratory analysis.
Can chain-of-custody issues help the defense?
Potentially.
A defense attorney may examine collection logs, laboratory records, evidence-room documentation, photographs, packaging, testing procedures, and testimony from the people who handled the evidence.
Depending on the circumstances, problems may support an argument that evidence should be excluded, that its reliability should be questioned, or that the prosecution should be required to explain inconsistencies before a judge or jury.
Even when evidence is admitted, chain-of-custody problems may affect how much weight a factfinder gives it.
Why does this matter in a Los Angeles criminal case?
Physical and forensic evidence can become a major part of the prosecution’s case. But the existence of an item alone does not necessarily answer questions about where it came from, how it was handled, or whether it remained in substantially the same condition.
A criminal defense attorney can examine the evidence itself as well as the procedures used to collect, preserve, test, and document it.
If you are facing criminal charges in Los Angeles involving disputed physical or forensic evidence, Simmons & Wagner can review how that evidence was handled and determine whether authentication, reliability, or other evidentiary issues may be relevant to your defense.