I think the police already have pretty good systems for that. If there is actual violence against them, then they can file charges against the known assailants, and have a pretty good chance those charges would stick.

Whereas with violence done by police, even if you have the best video in the world proving that they murdered someone on live TV, those charges probably wouldn’t stick. Or even be brought to court.

There needs to be a counterbalance to their overwhelming power in such matters.