The parents of the American businessman beheaded in Iraq and the U.S. government are in dispute over what happened to their son in the weeks before he was killed. A video showing the man, Nicholas Berg, being beheaded apparently by Islamic militants appeared on the Internet Tuesday. His parents have blamed the U.S. government in part for his death because their son was unable to return home as scheduled in late March because he was picked up by Iraqi officials and detained. His parents claim he was handed over to the US and detained for nearly two weeks. The US denies the charge but admits FBI agents visited Berg three times while he was in custody. It is still not known why he was detained, why he was questioned, and when he was abducted and killed. The Washington Post interviewed friends of Berg who said he may have been detained because he had an Israeli stamp on his passport and was suspected of being an Israeli spy. The U.S. is now saying it offered Berg a chance to leave the country but he declined.