Cops are just people, albeit, some have overly active violence tendecies, usually inspired by working with the most scummy part of the society. I've noticed in my 68 years on the planet that most cops are the unpopular kids from high school, maybe even the picked on ones that are out for revenge. That's not to say there aren't a few good men in law enforcement, but heavy on the "few". Power corrupts, and the police have that corrupting power. They eventually begin to believe they are above the law, the thin blue line. I mean, if you were working Narco, and came accross a couple of Kilos of pure peruvian flake and a couple a hundred grand, would it not be tempting to skim off a bit, maybe make the bad guys dissapear and keep the whole damn thing? Yeah I thought so. Walk a mile.