Congrats you've taken the cake for dumbest opinions in this board.
Apparently there is some random guy who was there who claims there was two shooters, so half my Facebook is all OMG CONSPIRACY!!!! Because definitely the one random guy didn't make it up to get famous or even just be confused based on the chaos.
Anyway, it does seem like the shooter snapped... but then again, if you just suddenly snap, maybe you have a gun or two and go on a rampage. He snapped and then managed to get ahold of an armory and plan out an elaborate death trap over a long period of time, I presume. That just seems like more than just "snapping."
He could've snapped weeks ago, which lead to the devising of a more elaborate plan than going on a rampage in the nearest Home Depot ten minutes after losing hs marbles. ---
Sigs are rather pointless, except if it's to showcase animation and images.