The Impact of Body-Worn Cameras on the Burden of Proof and Evidentiary Expectations: A Prosecutor’s Perspective

Damon Mosler, Deputy District Attorney, San Diego County, California

Upon learning that a local law enforcement agency was preparing to deploy body-worn cameras (BWCs), we as prosecutors had to wonder what this new evidence would mean to our presentation of cases in court. Would it mean more or less work? More or fewer trials? Better trial outcomes?

In its simplest form, footage from BWCs could be considered just another type of evidence collected by law enforcement to prosecute offenders. But the novelty and volume of this type of media, as well as the public spotlight on it, makes the evidence unique. BWCs often capture more than officers can remember or more than they observed, which can pose testimonial concerns. Because officers cannot view all of their recordings before they write a report, some details that do not make it into a report may be called into question during testimony.

Given the reactive nature of law enforcement, what, if any, criminal activity would be caught on the BWC footage? And how will juries, judges, and the public react to criminal cases without video evidence? In light of the emerging nature of law enforcement’s and prosecutors’ experience with BWCs, this paper provides some thoughts on the evidentiary nature of BWC footage.

Crime Charging Expectations: As a practical matter, prosecutors cannot view all of the BWC evidence on a given case before making a charging decision. Even minor cases can generate several hours of video, especially if multiple videos of the same incident have been recorded. Charging prosecutors often have less than an hour to make a decision on whether to prosecute and what charges to file. With the advent of BWCs, many in law enforcement have voiced concerns that prosecutors will not file charges without video evidence. In fact, because most prosecutors assigned to review charges understand that crimes are rarely caught on camera, lack of video evidence should not pose a barrier to filing charges. Only certain crimes require BWC footage review prior to a charging decision: those involving force or violence against the officer or (in some instances) by the officer, those involving interaction with a mentally unbalanced person (to view the person’s state of mind), domestic violence service calls (to hear and see the victim’s report of the crime), and driving under the influence cases (to observe the impairment).

Courtroom Expectations: Without a doubt, as more BWCs are deployed, more videos will be used as evidence in court. And jurors, exposed to a barrage of outside media accounts in which crimes have been caught on video, will likely expect the crimes before them to be on video. By introducing some video in court, prosecutors can help manage those expectations. Yet, as most associated with police work know, the critical evidence in a case will not usually show up on BWC footage. As a practical matter, the videos are used more frequently to reflect what a victim, witness, or suspect said, and to assess the trustworthiness of those statements. Footage of an officer’s initial contact with certain crime victims can serve as powerful and compelling evidence—much more so than a written report or in-court testimony months after an incident occurred. Prosecutors also rely on BWC footage to establish the on-scene true demeanor of the witnesses or suspects who testify about the events that occurred before the officers’ arrival. Videos may also be used to help make a crime scene “come to life” through video captured by the first responding officers. Because BWC videos generally reflect well on police officers and help juries identify with officers, prosecutors are looking for ways to present videos to juries more often. In terms of courtroom presentation, it is incumbent on prosecutors to manage jury expectations of BWC tapes through jury selection questions, through the introduction of relevant tapes, and by direct examination of officers.

Courtroom Challenges: When and how BWCs get activated will also be a point of courtroom contention. A delayed activation or premature stoppage of the camera will generate questions and doubts. When events or statements are not caught on video, the officers may be subjected to more intense cross-examination, and their motives and professionalism may be called into question. Triers of fact must understand that the BWC does not follow the officer’s eyes, so the officer can see things not on the video. Documentation and thorough reports will be critical. In addition, BWCs may capture more than the human eye can, and prosecutors may have to explain this in court. Because a BWC records in only two dimensions, it cannot capture the “speed of life” and seldom captures physiological cues given off in a contact. Prosecutors must work with testifying officers to explain to juries the limitations of BWCs in capturing the perspective, focus, history, and intent of the officer.

Evidentiary Matters: As with all evidence, how and when BWC recordings are received affects their ability to be used in court. Metadata labels, required on virtually all BWC recordings, provide sorting and organizing information and indicate the retention period for each video. Incorrectly categorized videos may be inadvertently purged by law enforcement before they are furnished to the prosecutor, resulting in missing evidence, which can imperil a prosecution. Late discovery of mislabeled videos can also delay a trial or limit admissibility, which could deprive the jury of relevant evidence that would paint a clearer picture of an event. Using the videos in court will require preparation of transcripts and, at times, redacted versions of the recording. Late rulings on what part of a video may be used and what must be excluded can also creating redaction and transcript difficulties that will limit videos from being used in certain cases. 

Trial Preparation: To prepare effectively for court with BWC evidence, law enforcement officers and prosecutors will have to spend time together reviewing videos to ensure that proper questions are asked in court. Such preparation will also help when there are discrepancies between written reports and videos. Without a mutual understanding between officers and prosecutors of what is or is not on a video and why, presenting videos can open the door to unanswered questions and negatively affect a case.

The Future: Gauging the overall impact BWC videos will have on the criminal justice system is inherently difficult, and the impact of BWC recordings in court remains to be seen. A video with strong prosecutorial evidence may lead to a plea by the defendant, but many other factors may also play a role in the defendant’s decision. A video that reflects poorly on a victim, witness, or officer may influence the decision of whether or not to file charges after video review. To quantify these outcomes would require possible disclosure of attorney-client communication or work product. Finally, juror evidentiary expectations will have to be managed, just as they were with the advent of DNA evidence.

One point is readily apparent: BWC evidence requires enhanced law enforcement and prosecution collaboration. In order for BWC videos to achieve effective outcomes, prosecutors must understand police field work well enough to know what will and will not be caught on video, and officers must help educate their courtroom partners about why certain enforcement actions unfold as they do. Conversely, prosecutors can point out to officers which recording practices help in court. Such mutual teaching and partnership can lead to improved evidence capture on BWCs that will lead to more effective courtroom presentations. 


Damon Mosler has been a San Diego County Deputy District Attorney for over 24 years and is currently theChief of the Economic Crimes Division. He has served as chief of both the narcotics division and special operations as well as a law enforcement liaison for the San Diego County Sheriff’s Department. He has taught on a range of topics including: case preparation, predator/club drugs, informant handling, 4th amendment law and body worn camera concerns. He is a body worn camera subject matter expert for the bureau of justice assistance.