Witness the case of Abu Musab al-Zarqawi, the Jordanian believed to be leading hundreds of Islamist militants in Iraq.

ECONOMIST: Chasing al-Qaeda

The terrorist group, led by Abu Musab al-Zarqawi, has released previous videos showing foreign workers pleading for their government's help.

CNN: Video?shows?8 Chinese held in Iraq

The CIA is checking claims that top al-Qaeda suspect Abu Musab al-Zarqawi was involved in the killing of Mr Berg.

BBC: NEWS | UK | Politics | Carey condemns Iraq beheading