This _________ document details the life of an item of evidence from the time it is found until it is no longer needed.

The correct answer is the Chain of Custody document. This document is essential in maintaining the integrity of evidence within a legal context. It provides a comprehensive record of who collected, handled, and transferred the evidence from the moment it is found until it is no longer required for legal proceedings.

The Chain of Custody ensures that the evidence has not been tampered with or altered, which is crucial for maintaining its admissibility in court. By documenting each individual who interacts with the evidence, it creates a clear, traceable path that validates the authenticity and reliability of the evidence presented in a case. This meticulous tracking is vital in both criminal and civil cases where the validity of evidence plays a key role.

In contrast, while a report may detail various aspects related to an investigation, it does not specifically trace the handling of evidence. Witness statements are personal accounts related to the case but do not track the evidence itself. Field notes, though important for recording observations during the investigation, also do not serve the specific purpose of detailing the lifecycle of an item of evidence.

Therefore, the Chain of Custody document is the appropriate choice as it uniquely fulfills the requirement of documenting the lifecycle of an item of evidence.