chainofcustody

Chain of custody refers to the documented, unbroken transfer of evidence from the time it is collected until it is presented in court or discarded. It tracks who handled the item, when and where it was moved, and under what conditions it was stored or analyzed. The purpose is to preserve the integrity of the item and establish a clear chain of responsibility for ultimate admissibility and reliability.

Core elements of a chain of custody include thorough documentation, control and accountability, and a formal transfer process. A chain-of-custody log or form accompanies each item and records the description, a unique identifier, date and time, custodian name, location, purpose of transfer, and preservation method. Packaging, labeling, and tamper-evident seals help deter contamination or substitution. Secure storage and routine verification of the item’s condition are also essential, with any transfers requiring note and sign-off by the receiving party.

In forensic, investigative, and legal contexts, the process begins at collection and continues through analysis, storage, and presentation in court. Any unexplained gap, alteration, or delay can cast doubt on the evidence’s authenticity and affect its admissibility. Clear procedures, trained personnel, and auditable records are critical to maintaining credibility.

Digital chain of custody applies to electronic data and artifacts. Practices include creating bit-for-bit images, calculating and verifying hash values, using write-blockers, and maintaining secure, access-controlled storage. Each action—copying, transferring, or examining data—is logged with time stamps to preserve a verifiable history.

Overall, chain of custody is a foundational concept for ensuring evidence integrity, accountability, and legal defensibility across disciplines.