Couple of notes:
Citizens in the area say they heard gunshots before the event.
The perp made extraordinary efforts to minimize human casualties. That rules out a trap for police and first responders. That also discounts Muslim terrorists.
The RV, explosives and materials used ate easily traceable. DNA is probably all over the place unless the perp was extraordinarily careful, but there are a lot of parts to this, and cameras everywhere. Even the clowns at the FBI will have suspects soon. (Of course,being the FBI, that’s not to say they will be the right suspects.)
They haven’t ruled out a body in the RV yet.
(Has anyone seen Lin Wood lately?)
I’m going to guess the perp was in the RV broadcasting the warning and when he could see no innocents were close, detonated the bomb. As for the why......
Haha...about Lin Wood.