I didn't study it to tell you how well it was synched, I think due to the far away shot it would be hard to tell, you don't have to move your mouth to scream, you don't even have to open your mouth to scream or shriek, yes the kid was a little strange, anybody going to iraq to build radio towers during a war has to be a little on the reckless side, and of course the issue with moussaiou using his email password, so hey maybe he joined al qaeda or the resistance, even if he did I can sure see al qaeda or the resistance saying let's whack this american to score some political points
but since he did die I don't want to lay that on him, especially with no proof of collaboration
anyway I see no reason for a conspiracy here, it's not like the americans need the bad publicity of a beheading, they had him in custody, if they wanted to they could have just thrown him in cuba, like johnny walker and then given him a trial