Updates on what I wrote earlier today: the shooter flew on Delta, not Air Canada, a one-stop flight from Anchorage to Ft. Lauderdale via Minneapolis, I think. With no stops in Canada, it is clear that he could check a firearm through to his destination in FL on a U.S. flight. It is alleged his gun case was the only baggage he checked ... nothing suspicious about that, right?
It is also now averred that some months ago the shooter walked into an FBI office in Anchorage claiming that U.S. intelligence agencies were forcing him to watch ISIS recruitment videos. He was taken for psych evaluation and declared (sic) not dangerous by someone who understood his/her job to be "move 'em out."
Apparently we're dealing with another 'known wolf,' someone the authorities had in their sights and let go for lack of immediate evidence of evil intent or of manpower, choose one. Matt Drudge has a photo of the Puerto Rican shooter giving a jihadi hand sign and wearing something that could be one of their trademark scarfs.
Until we reopen the mental hospitals and resume warehousing sad, broken people like this, we'd better get over being shocked by the occasional shooting spree. It is our conscious choice to only corral them after they commit an atrocity.
Snark about locking barn doors after escaped horses seem appropriate in this context.