Look I know you're furious about the situation but what's the point beating them up? You'll be the same crap. Easy thing to do: report to facebook about the fake account and call the police if there are death threats or harassments. Contact the school and report them. But since you're a guy and most guys won't do that, get their ip adress, locate their houses and send them mail on how you're going to kill them.
Eh that might send you to jail though. Please just report them because if you ever get caught you're in for it.