Thanks for the ping. The fact that some witnesses have seen more than one person makes me fear that it's AQ. I hope that it's not because if it is and one or two of them are captured for this, they can just get another AQ member or two to continue the shootings.
Another thing that worries me about the possibility of this being AQ is the idea that they could be using this to distract LE while they plot something big in D.C.