13 Tips When Recovering, Analyzing, and Preparing Audio, Video, and Digital Evidence for Court

Here are thirteen tips for attorneys, private investigators, law enforcement officers and of course everyday citizens, gathered over our years from working as forensic video, audio, and digital media files evidence experts. These tips may help you avoid making critical mistakes during trial, or even better, make you a hero to your client.

For additional assistance, contact us now for a free phone consultation. NCAVF also offers a California State Bar accredited MCLE continuing education class on properly analyzing and preparing digital evidence for court cases.

  1. Read reports and request all surveillance evidenceCameras are EVERYWHERE now. It’s almost strange these days if an incident is NOT captured at least partially on video. Home cameras record not only inside a residence, but often capture areas in the public domain. Investigate nearby businesses and homes, and search for surveillance cameras including Ring, Nest, and similar devices that might have recorded sidewalks and streets relevant to your event. Do forensic analyses of DVRs. Events are recorded by witnesses with smartphones; search for those by asking at scene, by capturing full dumps of cellphone evidence, and finding online with Facebook, Instagram, Twitter, and YouTube.Remember: It’s on YOU to find these materials!

  2. Assume a tight evidence recovery deadline. Home based CCTV video surveillance cameras and workplace security systems use DVRs and cloud based services that don’t save recorded video footage on their hard drives for long. Sometimes as long as a month will be saved, but often home surveillance systems will save the files only 4 days or a week before being deleted!If you’ve determined there may be surveillance video evidence, attempt immediately recovery, and unplug systems to prevent evidence from being auto erased.Home owners and business owners who have security cameras are not necessarily experts in operating their equipment, and they will likely have no idea when their footage will automatically erase. It could be a week, or it could be a year — every system varies. Do this investigative work immediately upon being assigned the case, and you might discover and save visual evidence that will make you a hero!

  3. Confirm security system time settings. It is common to find surveillance systems with the date and time set inaccurately. Compare the current time in the DVR to actual time, so that you can adjust your search to capture video of the intended event. Note the deviation as you may need to explain this time difference in court.

  4. Ensure your evidence is the highest resolution possible. When you are given surveillance evidence, you’ll want to ensure it is the highest video resolution possible. Email and texting often introduces compression to video and audio. In addition, even if the evidence was exported directly from a DVR, compression may have been accidentally introduced. This means you should spend time to research and find the most original (“proprietary”) version of the video possible.Do not rely on your phone to record the screen unless absolutely the only option, and do not convert the file because this may give you reduced resolution. If you do, label that new file as compressed.

  5. Take possession of the DVR and camera. If your case is important enough to you, you’ll want to take the device that recorded the security footage, and also the camera that recorded the signal, whether it was a smartphone, dash cam, GoPro, or a security surveillance camera. Why should you do this? To prove or disprove certain evidence in court you want to maintain the option to exactly recreate the scene of the crime — this requires information including the computer system settings used when capturing the video and information about the actual camera including the lens through which the video was captured.Details of a case can be clarified by understanding the system settings make and model, camera, and lens used in making your video or audio recording.

  6. Don’t accept your audio or video evidence at face valueVideo footage that is too dark or too bright may contain valuable details. And audio that is too loud or too low or noisy can sometimes be clarified and analyzed. Collect and save all evidence, no matter how dark, bright, over exposed, unclear and unintelligible it may seem to you, and allow experts to enhance, clarify, and analyze to uncover hidden details.Here is an example of dark footage evidence made brighter in our labs.

  7. Research the technology behind the evidence. A few examples are metadata, frame rate, video compression, and camera lenses. Learning about a security system, smartphone, officer body camera or dash camera may help explain why a recording looks and sounds like it does. Technical research can answer questions such as: 1) How much activity from the incident did the security system miss, and why; 2) What cameras were used, and how do lenses on those cameras alter what is seen on video recordings; 3) What does metadata reveal about the nature of the evidence?

  8. Determine measurements of a suspect’s height, determine distance, car speed, and object size through forensic video evidence analysis. What forensic measurements, if they can be determined, would be helpful to your case? There is a fascinating tool at your disposal — 3D crime scene reconstruction software. Combining video of an incident with new measurements taken on scene can calculate specific details — an individual’s height, distance from objects or people, location within a crosswalk, object width, direction, and speed.


  10. Give video forensic experts sufficient time. Audio, video, cellphone, and hard drive forensics is both an art and a science. It requires time to delve into digital evidence and uncover details that might otherwise be overlooked. The more time we are given to view video, listen to audio of an incident, or analyze hard drive files, the more we consider alternative methods for enhancement and analysis and recognize crucial details to help your case.Presenting the results of the analysis clearly to a jury is equally important, and this also takes time — to test, adjust, and filter visual elements that keep the data accurate, concise, and visually powerful.

  11. Just because enhancement couldn’t be done before, doesn’t mean it can’t be done today. As technology improves, there are more advanced methods available to enhance audio and video recordings and to recover and analyze cellphone and hard drive files. This proved true in our case involving deputy Ivory Webb. If we had gotten the Ivory Webb case a year earlier, the audio could not have been filtered as well because a new version of the software came out that provided a better tool for audio filtering.Software and hardware is regularly updated to enhance and analyze digital signals in a more accurate, efficient, and affordable way than previously available.

  12. Make your evidence “Attorney Proof” and jury friendly – Present evidence smoothly in court. Presentation of your evidence is critical, especially to a judge and jury. When presenting your clarified audio, video, or any digital media evidence, make sure it’s as simple to use and understand as possible. The goal is that anyone should be able to “get it.” Create PowerPoints and files that play with the minimum of effort, so an attorney can focus on the argument. Each prepared clip should play exactly the specific section of video or audio evidence needed — no more and no less.Whoever will be operating the playback of your evidence should practice with the same system (e.g.
    computer and screen) you’ll actually be using in court, and consider having a backup player in case of technical failures. The jury will be using your evidence for deliberation, so it is absolutely necessary for them — without instruction or supervision — to easily load, view, and understand the digital evidence. If the jury thinks your presentation of the evidence is unprofessional or not smooth and aesthetically pleasing, you may lose their attention and confidence (even if your case is tight)!

  13. Involve your video expert in the setup of equipment before the court case and bring your digital media expert into court during trial. In the days and weeks before court presentations, be sure to test all video and audio cables and equipment. When your presentation of the video or audio evidence is smooth, it keeps you on the good side of the judge and builds trust with the jury. On numerous occasions, we’ve been told by the opposing side, “You can plug right onto our systems.” But when we test their setup in the days prior to the case, their playback system isn’t operating correctly. So for best results, work together with your forensic video or audio expert to test equipment being used to present the evidence to see and hear the evidence most comfortably.If possible, have your video expert physically at the trial. An on-hand video and audio expert will solve any technical glitches immediately, smoothly operate video and audio playback, and free up counsel to focus on arguing the details of the case instead of fumbling with technological devices. Allow your digital media forensic expert to be a partner in your success and help you make changes to your cross or closing argument at the last minute in response to a presentation by the other side. We’ve seen in court opposing lawyers tripped up by digital media playback, which often results in losing a key moment to make an affective argument – especially during cross examination when last second changes are common. Don’t let this happen to you.

Bottom line

Maintain trust of the jury by hiring an experienced forensic video expert and an expert witness that exhibits confidence and honesty. In today’s technology-driven world, people understood more than ever that images, sounds and video can be manipulated through unconventional editing techniques. Jury members especially understand this. Most likely they have seen nutty conspiracy theories in films, and they have watched too many bad TV shows about cops and trials. But the right expert witness can put their apprehensions to rest by being a trustworthy source of information, by clearly testifying to the chain of evidence, and by explaining the relevant aspects of the forensic video and audio enhancements. Once the audio or video evidence is declared legitmate by your expert witness, your jury can then focus on the evidence and make an intelligent decision.