That can’t happen, police gotta police and even another system won’t change that. My dad has a "colleague" who used to be a police officer in the last 2 years of the GDR, after the wall fell he joined a neonazi party for a few years.

The uniforms, weapons and authority simply attract a certain type of person and that won’t change. The only thing that can be done is to restrict the hell out of the police so the really foul ones can’t even get in and the one rotting can quickly get kicked out.