I'm assuming you're mostly asking in relation to the recent incident in America. I've no solution to that sort of thing, certainly looking from the outside in, policing in America appears very adversarial with a "them and us" attitude and obvious ingrained racist undertones. It baffles me how police can get away with what they do there.
That's not to say policing is perfect where I'm from but where I'm from police police with consent of the communities they police, at least that's the theory.