New York (CNN) -- Osama bin Laden's son-in-law was found guilty Wednesday in New York of helping al Qaeda terrorists conspire to kill Americans and other terrorist activities.
Federal prosecutors said at Sulaiman Abu Ghaith's trial that the Kuwaiti cleric played a crucial role as the organization's principal mouthpiece and recruiter, helping "restore al Qaeda's trove of new terrorists" as deadly missions turned its members into martyrs.
"Without people like him, al Qaeda dies with every suicide attack," Assistant U.S. Attorney John Cronan said in his closing argument Monday.
The government did not allege that Abu Ghaith served an operational function or had a direct hand in carrying out the attacks.
The trial was held blocks from the site of Manhattan's World Trade Center, and several survivors of the attacks and family members of victims attended.
Abu Ghaith testified last week that he never joined the ranks of al Qaeda and assisted bin Laden only as a speaker on spiritual topics. Known in the Persian Gulf region as a religious scholar and fiery orator, Abu Ghaith met the al Qaeda leader in Afghanistan in June of 2001, according to testimony. He denied advance knowledge of the 9/11 attacks but said he'd heard talk that "something big" was about to happen. He moved his family from Afghanistan to Kuwait days before the September 11, 2001, attacks on New York's World Trade Center and the Pentagon.
Abu Ghaith, 48, could face life in prison.