CAIRO – Al-Qaida's chief bomb maker, Ibrahim al-Asiri, who was behind the 2009 Christmas Day plot to down an airliner over Detroit and other foiled aviation-related terror attacks, was killed in a U.S. drone strike, Yemeni officials and a tribal leader said Friday. The killing of al-Asiri deals a heavy blow to the group's capabilities in striking western targets and piles pressure on the group that already lost some of its top cadres over the past years in similar drone strikes. A Yemeni security official said that al-Asiri is dead; a tribal leader and an al-Qaida-linked source also said that he was killed in a U.S. drone strike in the eastern Yemeni governorate of Marib. The tribal leader said that al-Asiri was struck, along with two or four of his associates, as he stood beside his car. He added that al-Asiri's wife, who hails from the well-known al-Awaleq tribe in the southern governorate of Shabwa, was briefly held months ago by the UAE-backed forces and later released.