A video grab image on an Islamist internet site shows American hostage Eugene Armstrong prior to his execution September 20, 2004. A militant group headed by al Qaeda ally Abu Musab al-Zarqawi said on Monday it had beheaded an American hostage and posted a video of the killing on the Internet.The video, identified the hostage as Eugene Armstrong and showed a masked man sawing his head off with a knife. REUTERS/HO