My opinion is that the local government will pull out all the stops to prosecute and win. One thing those in power universally don't like is any form of vigilantism, even if they aren't doing their job of protecting the citizenry. It's a sad state of affairs, but I see this going to trial and the kid doing time for it.
Do tell: how will the prosecution overcome the burden of proof to disprove the self-defense affirmative defense?