Establishing a chain of custody is the first step in any audio or video forensic investigation. This includes audio/video forensic enhancement, audio/video authentication and voice identification. Where did the evidence come from? Who created the recording that is being entered into evidence?
A chain of custody is the documentation of who did what to evidence and when was it done. A chain of custody includes people, dates, places, activity and the recording of that information to establish the chain of custody. What has been done since the evidence was created? The chain of custody refers to both digital and analogue audio or video evidence.
The chain of custody for a piece of evidence is important to the legal community because it adds credibility to the audio/video evidence. However, it is common for law enforcement and others in the legal community to often overlook establishing a chain for audio/video evidence. It’s not because of neglect but more often due to lack of training or understanding the importance of the process.
Unfortunately, audio/video recordings are sometimes entered into evidence without documenting the evidence recovery process. When this is the case, if both parties agree that the evidence is acceptable, and tamper free, the audio/video recording is established as the ‘original’ and the chain of custody begins there.
An audio/video chain of custody begins with the evidence recovery process. This is the process of forensically removing the original audio/video recording from the recorder that created it. Based on our experience at Primeau Forensics, once both parties in a criminal or civil litigation agree on an original, they request each side’s forensic expert to establish a protocol for recovering the audio/video evidence. This protocol is written step by step instructions created by one of the experts, then negotiated and or modified and revised until the protocol is established.
Over the last 32 years practicing as lead expert at Primeau Forensics, Ed Primeau has worked with evidence recordings from client lawyers who received recordings from the police. Whenever evidence is not retrieved personally, the police reports, depositions, and other court documents that accompany the evidence must be carefully read to understand how it was acquired. This paper trail must establish a timeline; a chronological listing that accounts for the recovery, custody, transfer and storage of the evidence because the lack of an established chain of custody can easily overturn a conviction on appeal.