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How to ensure proper chain of custody with digital video evidence

Agencies must ensure that video evidence – particularly video that was not collected by the on-officer camera – has not been doctored or edited


In this image from video provided by the Spokane Police Department police body camera video, police officers arrest a mentally ill woman in October 2014.

Photo/Spokane Police Department via AP

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Digital evidence, while unique and distinct, is not unlike other items of evidence when it comes to use in court. The evidence must be preserved by the agency. With digital evidence this can entail keeping and maintaining memory cards, portable USB drives and other storage devices. This includes the massive servers needed to store and manage digital evidence collected via on-officer video cameras.

Just like the handling of physical evidence such as fingerprints, confiscated weapons, drugs and other physical objects, digital evidence must also be authenticated in court, as the evidence proffered has to be proven to be true and accurate. Video in particular needs to be proven to be an accurate depiction of what the proponent of the evidence purports it to be.

Terry Dwyer, an attorney who represents police officers, says that the basics behind this are no different than the admission of a photograph from a SLR camera or a document. However, because of the nature of digital evidence and its integration into so many facets of modern life, it presents challenges of its own, particularly in regard to authenticating the evidence.

“For example, some digital evidence, such as a Facebook page, can be created by someone other than the party charged, or potentially accessed or hacked,” Dwyer said.

When it comes to video evidence, particularly video not collected by the on-officer camera such as security camera or cell phone video, great pains must be taken to ensure that the video has not been doctored or edited. This may require the assistance of forensics experts such as those available from the FBI at Quantico. It’s potentially a time-consuming extra step, justified by the prevention of important video evidence being tossed out due to lack of authenticity.

Adhering to policy and procedure for digital video evidence management

Dwyer says that police agencies must update their evidence-handling guidelines to include the handling of digital evidence.

“As with any aspect of police work, if there is a policy in place and the policy was followed, there will not be an issue,” Dwyer said. “Issues arise when there is either no policy or the policy was not followed.”

Key to handling digital evidence is for the handler to know the technology and how to preserve it so it is not lost and cannot be tampered with. In terms of admissibility, it is always helpful to have someone testify who has expert knowledge of digital forensics.

“I would say other than the special type of evidence that digital images and videos provide, and the possibility of it being tampered with or lost because of poor handling, there is not much difference with the requirements in handling as far as protocols. Have a policy, follow the policy and keep video stored in a secure location, as well as having it numbered and accounted for through a department evidence-tracking system,” Dwyer said.

maintaining chain of custody with digital video evidence

Chain of custody is an important and critical part of gathering evidence that sometimes gets forgotten or is not rigidly followed. Departments are much better in this regard than they were many years ago, but there are still horror stories.

“To give an infamous example of the impact poor chain of custody can have on a case look no further than the OJ Simpson prosecution in LA and the handling of blood evidence. The defense attorneys had a field day attacking the chain of custody. A broken chain of custody can lead to inferences – which aren’t facts – which can lead to a reasonable doubt in a juror’s mind. Chain of custody, which pertains to law enforcement’s handling of the evidence (collection, transport, etc.), is required to show there has not been or it is improbable that there has been any tampering or substitution of the evidence. It provides a foundation for the evidence to be reliable and admissible.”

Keeping to the tried and true means of police investigation

Dwyer says that losing video evidence due to a chain of custody breach is not fatal as long as there is no complete failure of proof. Remember that digital evidence is but one piece of evidence in a case. The standard tried and true means of investigation cannot be forgotten or ignored because there is a video of the crime. Police still need to do what they best: question and gather more evidence.

“I recall a commercial burglary case where the perpetrator was caught on a recently installed security camera. It was former employee who was identified by the owner. I called the D.A. and told him what I had and jokingly said, ‘I don’t we need a confession in this one.’ He replied that he really wanted one, despite the video and the owner’s ID of the perp. I arrested the perp after further investigation and obtained a detailed confession. Even if we lost the video, my investigation had solidified the suspect’s guilt with not only his confession, but also interviews with others and some physical evidence that was obtained.”

The moral of the story, Dwyer said, is that just because you have digital evidence, doesn’t mean you stop investigating and gathering further evidence of a non-digital nature.

Doug Wyllie writes police training content on a wide range of topics and trends affecting the law enforcement community. Doug was a co-founder of the Policing Matters podcast and a longtime co-host of the program.