IT guy gets fired and goes rogue.
I just have to wonder how dependent they'd made themselves on this clown. There are things one does in cases like this, over and above the 'lock the users accounts'. (I've been on a couple of those phone calls, including once having to head to office at 22:00 and meet with police officers who wanted the logs of *everything* I typed into a CLI.). There's much to be said about incompetence here. On both sides.