Bud White murdering the black rapist.
The scene in this movie which always bothers me is when Bud White walks in on the unarmed black rapist, murders the rapist even after he raises his hands up in the air, and then covers up the scene to make it look like the rapist tried to shoot at him.
I know the guy was a sick rapist, and everybody here probably believes it was justified for White to kill him, but... the guy did raise his hands up in the air. Also, he looked genuinely scared for his life. The fact that he is humanized in that moment makes it difficult for me to enjoy his death.
The movie is all about this sort of thing, of course -- cops willing to break the law in order to get criminals -- but to me, this is the worst crime which White commits in the film. Instead of trying to arrest an unarmed rapist, he acts as judge, jury & executioner, and murders him. That has always made it hard for me to truly like Bud White. I guess that's the point, though.