I don't see why cops have to treat people bad. In the movies and TV shows I see, cops do act reasonably as decribed in your scenario and the BGs always (or almost always) end up brought to justice. And Hollywood should know, because they are experienced. All told, there must be millions of hours of police shows made, so they must be right, right? I thought so. Perhaps cops from your "real world" should and could learn a thing or two from Hollywood.