Marty McFly: "What about the police, Biff? They're gonna match up the bullet with that gun."
Biff Tannen: "Kid, I own the police! Besides, they couldn't match up the bullet that killed your old man."
Marty McFly: "You son of a..."
Biff Tannen: "I suppose it's poetic justice - two McFlys with the same gun."