What is a significant reason for collecting a first account of an event immediately?

Collecting a first account of an event immediately is crucial primarily to prevent witnesses from collaborating their stories. When witnesses have time after an event to discuss their accounts, there is a risk that their recollections may become influenced or altered based on one another's perspectives. This can lead to a distortion of the facts, as individuals may unintentionally conform their memories to match those of others. By capturing their first-hand accounts promptly, investigators can obtain more accurate and reliable testimonies, reflecting each witness's unaltered perception of the event. This practice helps preserve the integrity of the evidence and aids in the fair adjudication of the matter at hand.

The other options serve different purposes: documenting for insurance is important but secondary, ensuring all witnesses are present is often impractical, and creating a comprehensive understanding for the jury generally occurs later in the process. The immediate collection of first accounts directly addresses the integrity of witness testimonies, making it a significant reason in the context of investigations.