I find it odd that nobody has yet mentioned Columbine. Another insane killing spree, perhaps? Black clothes, etc.
There have been at least a half dozen of these plots broken up since Eric and Dylan decided to become cult heroes.
Still, this doesn't seem to fit the Columbine profile. These three sound like grown men, not kids working through their teenage angst with violent fantasies. The Columbine kids knew the victims, and hated them. These thugs don't have a clue whom they're shooting.