I got the impression there is something dissimilar about last night's shooting (compared to the MD shootings) that is making them hesitate, although that wasn't stated at the last press conference.
I've been wondering about the timing of this with the release of information that al Quaeda was planning this kind of thing. Could someone be pre-emptively copying al Quaeda? Whoever it is, is nuts, so the mind boggles trying to figure out which species of nut.