An Iraqi extremist group has broadcast an internet video apparently showing a hostage being shot dead.
Ronald Schultz was captured and filmed earlier this month
The Islamic Army of Iraq said the footage showed the death of American contractor Ronald Allen Schulz, whom it claimed to have killed last week.
Mr Schulz - a former US marine who worked as a contractor in Iraq - was reported captured on 6 December.
There is no independent confirmation of the identity of the man on the film as the face is not visible.
The al-Qaeda-linked Islamic Army, which first emerged in 2004, has abducted and murdered many hostages.