A person must become a documented part of a piece of evidence's chain of custody when she or he:

The correct answer is that a person must become a documented part of a piece of evidence's chain of custody when they physically handle the evidence. The chain of custody is a fundamental principle in evidence management that ensures the integrity and reliability of evidence throughout the investigative process. It requires that every individual who handles or interacts with the evidence must be documented to maintain a clear, traceable history of who possessed or controlled the evidence at any given time.

When an individual physically handles the evidence, they assume responsibility for its care and preservation, which makes their identity part of the chain of custody. This documentation is crucial in legal proceedings, as it establishes that the evidence has not been tampered with, altered, or contaminated, thus preserving its admissibility in court.

Participating in cause-determination activities, becoming an active member of the emergency response, or setting up control perimeters are important roles within a response team but do not directly impact the chain of custody of evidence unless those actions involve the actual handling of the evidence itself.