I wish I hadn't watched it, seriously...
We know there are sick people in the world, but to see footage like that...
As for the blood, I do see some dripping out. There is plenty on the ground too, a lot of it probably already came out beforehand. It is strange that he doesn't resist, but we all react in different ways.
I am open to the option that it could have been done by people we don't expect it to be, but the girl's story on DU is just supposition, snipping in convenient parts of the article and rewording (e.g. had to get to Jordan, Turkey or Kuwait vs. would come home through Jordan, Turkey or Kuwait).
Where's the motive? She doesn't even know. With all we hear about anyway, what could he have possibly seen that would make it necessary for him to die (by US hands)? I could easily make suppositions that would make the situation make sense. In any case, like his parents, I see the US as being responsible anyway, because they detained him without cause.