What about the police, Biff? They're gonna match up the bullet ...
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 bitch!
Biff Tannen: I suppose it's poetic justice. Two McFlys with the same gun.