The purpose of a witness statement is:

The purpose of a witness statement is fundamentally to help police document the facts in issue. Witness statements serve as crucial pieces of evidence that capture an individual's account of events related to a crime or incident. By documenting these facts, law enforcement can establish a clear and accurate narrative of what transpired, which can later be referenced during investigations, in legal proceedings, and in preparing cases for trial.

Witness statements are factual representations of what the witness observed or experienced, rather than opinions or interpretations. This documentation is essential for building a reliable case, as it allows officers to compile a comprehensive overview of the incident from multiple perspectives. The accuracy and detail within these statements can significantly influence the direction of an investigation and the viability of prosecution in court.

The other options focus on aspects that, while relevant to the broader context of law enforcement, do not directly address the primary purpose of witness statements. For instance, while aiding in a witness's testimony is an important aspect of gathering information, the primary goal remains to detail the facts. Establishing credibility of witnesses may be a consideration once the statements are evaluated, but it is not the statement's main purpose. Lastly, providing opinions is contrary to the intent of a witness statement, which seeks to remain objective and fact-based.