I think the perp was a boozer.
My best guess is the guy ran into a bad gambling streak, lost an obscene amount of money, blamed it on the casinos “rigging” against him, and sent the girlfriend to the Philippines, wiring her an amount of money to keep her comfortable.
He used the comps to get the room (no way else to get a room there that weekend) to give the casino “one last chance to make good” which failed and explains why he waited until the last night to carry it out, and and took out his revenge on the casinos by shooting up the concert.
Gambling addicts are very, very dangerous if they have violent tendencies.
I’m numb to all of this. I can’t believe this happened here.