What didn’t come up in the deliberations was whether we trusted the police. We didn’t have to — not because they didn’t provide crucial testimony in what turned out to be a long chain of evidence connecting the murder of Tyrese Davis to Craig Williams but because we never had to take their word for it. The reason: body cameras. Virtually every important moment — from the arrival of police at the scene where Davis was shot to the aftermath of the carjacking to the traffic stop on Route 40 to Mr. Williams’ arrest — was captured on a body camera. We saw exactly what the police did, what witnesses told them and where they found evidence. Trust simply wasn’t an issue. Many police officers were reluctant to adopt body cameras, and so were some prosecutors (notably Baltimore County State’s Attorney Scott Shellenberger), but from a juror’s perspective, so long as the police are doing their jobs, as they all were in this case, video is your best friend. (I talked to Mr. Shellenberger after the trial and made this point; he agreed and said he had come to see the error of his earlier objections.)