Body cameras are yet one more tool, just like dashboard cameras in patrol cars, to increase the chance of creating a evidentiary record of police action. Studies indicate they help more than they hurt. The Seattle Police Department plans to outfit all its officers with body cameras.

But they are not the solution to America's police brutality problem, as the NBC News report below on the brutal 2014 arrest of a Florida man named Derrick Price illustrates. One of the officers who pummels Price, who deliberately lays down and surrenders, is wearing a bodycam. But the footage doesn't show the beating. Then, as the officers shout "Stop resisting!", the bodycam is switched off. NBC suggests the footage, in and of itself, was misleading.

Instead, it was surveillance video from the parking lot that showed how the police beat the man up, leading to the indictment this week of one of the officers. The officers had charged Price with resisting arrest.