On-camera interrogations are increasingly common with state and local police, and now in a sharp change in policy, the FBI will require its 13,000 agents to record nearly every suspect interview starting next month.
It can be a powerful eyewitness, according to Assistant Chief Russ Hamill of the Montgomery County Police Department in Maryland, near Washington D.C.
"It probably benefits officers far more than it ever hinders an officer," Hamill said.
His officers have been using cameras for more than 10 years in patrol cars and interrogation rooms, explains CBS News' Jan Crawford.
"The cameras are just second nature now," Hamill said. "They offer very good evidence for prosecution or, on the other side, to exonerate somebody."
For decades the FBI resisted, using nothing more than pen and paper to document interviews in the belief that their word should be sufficient evidence for a judge or jury.
Phil Mudd served as the FBI's senior intelligence officer after the Sept. 11, 2001 terror attacks.
He said FBI agents have been "accustomed to getting on the stand, in a proud organization, to say 'look, I was the one who did the interrogation. I can confirm and I'll swear to confirming what this defendant said to me.'"
In an era where everything is recorded, however, juries now expect to see the evidence; how suspects react, whether they seem evasive or contradictory during interrogation.
In Montgomery County, there was some resistance when the department announced it was installing cameras in patrol cars. But Capt. Darren Francke said that was largely down to anxiety over the unknown.
He said some officers had fairly mundane concerns: "Will my sergeant be watching me? Is the chief going to see me scratching my nose?"
But Francke said the officers quickly learned that the camera could be their friend, especially when a defendant accuses them of abuse.
"They can say, 'absolutely, I did not,' and immediately show on the video that at no time did an officer lay hands on this person," he explained.
In other words, the proof is in the video, and soon, it will be for the FBI, too.