I'd thought of that, too - just a couple hanging out across the street from the monument and when someone blew it up they decided they'd better leave. On the other hand, the police are going to want to speak with them to see if they saw anything, etc.

It looked to me like there's some kind of (spot) light off to the left and someone launched a missile/rpg from just behind the light. Agree with you about the planned aspect of it. This wasn't a bunch of sloppy amateurs.