Amateur video shot from a cell phone can be important evidence of a variety of different crimes: assault, property crimes, drug crimes and even homicide. But you may not always recover the video from a suspect or victim. If it comes from a witness, you need to take a few things into account before asking them to hand their phone over.
1. Can you “collect” a phone video by simply watching it?
In New York City, police collected bystanders' cell phones that contained videos taken of the August Times Square confrontation with, and fatal shooting of, Darrius Kennedy. According to the New York Times:
After (bus ticket agent Edgar Delgado) sent his video to news media outlets, including NBC and ABC, right after the shooting, he said, a detective asked to see his phone, and it was taken to a nearby police vehicle.
“I could see them watching the video inside the truck,” Mr. Delgado said, adding that the police had him wait for several hours at the crime scene.
Is it enough to watch the video and document what you see? Probably not. Picture resolution may not be optimal on a small screen, so the video (or the entire phone) will require analysis by trained professionals. Also, you may not have a suspect in custody, and you may need an image from the video to help identify the wanted subject. Once you apprehend a suspect, you may need that video evidence for trial.
Could you ask the civilian who took the video to email it to you, or could you download it from a video sharing site like YouTube or Vimeo (assuming it was shared there)? Depending on the crime’s severity, think again:
2. Can you prove that video was unaltered?
With digital evidence, authentication is critical because it can be quite easy to manipulate. Can you be sure that the images you’re viewing on a victim’s phone at the ER weren’t downloaded a few hours ago in a bid to get a rival arrested? That a loved one didn’t alter them before uploading in order to make injuries stand out more?
Granted, it would be hard for anyone to alter a video in a situation like the Kennedy shooting. But that’s not the only situation you’re likely to find cell phone evidence in. You might be asked to review a video of an assault that happened days or weeks ago. The phone and its images may have passed through multiple hands before yours -- the equivalent of civilians trampling all over a crime scene before you’ve had a chance to cordon it off and preserve its evidence.
Whether on the phone or online, you can validate the phone’s evidence through corroboration, but this may not carry as much weight with a jury if a defense attorney casts doubt on its authenticity.
Simply downloading a video from the internet or even email isn’t the same as preserving the original recording of an incident. It may be impossible to determine if the video was altered before it was uploaded. However, a trained forensic examiner’s examination of cell phone data can be helpful in providing information about when the video was created and if it has been modified.
3. Is your testimony good enough on the stand?
Are you prepared to talk about digital evidence, how it’s stored, and how that storage differs from phone to phone? Do you have a sufficient understanding of how the digital evidence collection tools you use work, and are you prepared to testify about it?
4. What if it's a video of a sex assault on a minor? How do you preserve the video, but still wipe it from the witness' phone so they're not in possession of child pornography?
In Hightstown (New Jersey) last August, a witness to a sex assault on a 15-year-old boy filmed the incident on his cell phone, then dialed 911 and handed the phone to police to record the evidence.
So what did police do? The article doesn't say. But it should be plain that you can’t note what you saw in a report and give the phone back without erasing the contraband video. Simply saving a copy to a computer is, again, like picking up a casing at a crime scene without bagging and tagging it (not to mention that you’ve now contaminated another computer with the contraband video). What do you do?