NEW: The synagogue attacker jammed his truck into a hallway, couldn't get out, and then shot himself in the head when confronted by security officers, the FBI says. "His engine compartment catches on fire, and at some point during the gunfight, [Ayman Mohamad] Ghazali suffers a self-inflicted gunshot wound to the head.” “In the bed of the truck, we found large quantities of commercial grade fireworks and several jugs of flammable liquid we believe to be gasoline."