training isnt going to do anything with people who have no regard for human life... just like there are people who sign up for the service so they can go and kill in iraq, you have people who join the police department because they want to be above the law and have the ability to kill if they want...
i remember back in LA around 85 a buddy of mine (a crip) that i went to highschool with was routinely harrassed by one of LAPD"s finest... this cop and one of his buddies served up a beating on him and one of his associates that put both of them in the hospital... i cant remember the gist of it, but they murdered dude in front of his valley home in front of his wife and child...
some people just have that killing vibe...