as far as it being al Qaeda related, i don't think so, the would of done alot more damage than that, however i wouldn't be suprised for it to be a nut group.
al qaeda seem like a group that would rather fail at attempting something big that would inflict mass casualties rather than pull off something small that only kills a few people.
tell that to 9/11 or any of the other mass killings they've done. I still stand by it most likely being either home grown or a small group. if it were al qaeda they would of taken credit for it already.
im not trying to minimise 9/11 or anything, just saying that even their failed attempts on us soil have often been pretty big as in the intended devastation and body counts that would have occurred.
