After watching the video I'm not real sure that they killed him but seeing the end result it's hard to deny that they killed someone.
I've seen a number of these videos and this one is completely different than any of the others. It seems scripted and rehearsed to me. I suspect another video of Sotlof's beheading will appear in the next day or so.
I couldn't find a video of the actual cutting, but the head on the body after sure looks like him
There is no video of the actual beheading that I could find, all you see is the terrorist standing behind him as he starts to cut his throat, then it cuts to the end result. It was professionally done (the video) so the American media could air it on tv. That's their reasoning (supposedly) for not showing the murder as it happened.
