 Did he telegraph his intentions in advance? Were there clues missed? We don't yet know the man's name or his motivation or his background. And our sources are telling us that one of the reasons we don't is because the intelligence agencies and the law enforcement officials want to know more first. And so they're keeping a very tight lid on this circumstance so that they can feel confident that they have dug as deep as they can. And then they'll let the rest of us know.