Chain of Custody
Documentation showing who had possession of evidence and when, from collection through presentation at trial.
What You Need to Know
Chain of custody documentation shows: (1) who obtained the document, (2) when and how it was obtained, (3) who has had possession since acquisition, (4) any transfers of custody, and (5) security measures preventing alteration. While critical for physical evidence like drugs or weapons, chain of custody also applies to electronic documents in e-discovery. Proper exhibit marking with dates and identifiers helps establish chain of custody by creating clear tracking from acquisition through trial presentation.
Relevant Practice Areas
Frequently Asked Questions
Is chain of custody required for all exhibits?
Chain of custody is most critical for physical evidence that could be altered, substituted, or contaminated (e.g., drugs, weapons, biological samples). For routine business documents, less rigorous tracking is required—authentication typically involves witness testimony that the document is what it purports to be. However, for contested documents or ESI where tampering is alleged, detailed chain of custody becomes essential.
How do I establish chain of custody for electronic evidence?
For electronic evidence: (1) document how the data was collected (forensic imaging, email export, screenshot), (2) maintain hash values to prove no alteration, (3) log all access to the files, (4) store originals on write-protected media, and (5) provide metadata showing creation and modification dates. Use forensic preservation tools that generate audit logs automatically.
What happens if chain of custody is broken?
A gap in chain of custody may result in exclusion of evidence if the opposing party challenges authenticity. However, minor gaps may be cured through testimony explaining the gap or showing the evidence was secured and unchanged. Courts evaluate on case-by-case basis weighing the likelihood of tampering against probative value.
When It's Used
Critical for physical evidence and electronically stored information (ESI)
Example
"A log showing the seized hard drive was collected by Officer Smith, stored in evidence room #3, examined by Forensics Analyst Jones, and produced to opposing counsel on [date]."
Related Terms
Authentication
The process of proving that evidence is what it purports to be before it can be admitted at trial.
Metadata
Hidden data embedded in electronic documents showing author, creation date, edit history, and other file properties.
ESI (Electronically Stored Information)
Digital evidence including emails, databases, social media posts, text messages, and metadata. Subject to special discovery rules.
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