WASHINGTON – An American student from Northern Virginia was convicted yesterday of plotting with Al Qaeda to kill President Bush and trying to mount a September 11-style terrorist attack inside America.

Federal jurors convicted Ahmed Omar Abu Ali on all nine counts against him, including conspiracy to assassinate the president, conspiracy to commit aircraft piracy, and providing material support to Al Qaeda. The Falls Church, Va., man faces up to life in prison when he is sentenced February 17.

The verdict in U.S. District Court in Alexandria, Va., on the jury’s third day of deliberations, brings to a close one of the most hotly contested terrorism cases brought since the September 11, 2001, terror attacks. Abu Ali, 24, was arrested in Saudi Arabia in June 2003 and held there for 20 months. His parents mounted an intensive campaign for his release, suing the American government and accusing it of condoning the torture of their son.

But Abu Ali was charged with a variety of terrorism counts when he was flown back to America in February. Prosecutors said he had confessed to his Saudi jailers that he joined an Al Qaeda cell in the kingdom and was determined to kill Mr. Bush by shooting him on the street or blowing him up with a car bomb. Law enforcement sources have said the plot to kill Mr. Bush never advanced beyond the talking stage.

Abu Ali said the confession was false and was beaten out of him by the Saudis, who whipped him on his back so hard it turned bloody. His lawyers portrayed him as a polite kid from Northern Virginia who went to Saudi Arabia only to pursue religious studies.

Khurrum Wahid, an attorney for Abu Ali, indicated that he would appeal. “Obviously, the jury has spoken, but the fight is not over,” he said. “We plan to continue to use the justice system to pursue our client’s innocence.” Members of Abu Ali’s family declined to comment.

The trial revolved around the confession prosecutors said he gave to his Saudi jailers. Saudi security officers testified via videotape from depositions they gave in Saudi Arabia, insisting that Abu Ali was treated well and confessed willingly.

Prosecutors told the jury that Abu Ali admitted that he had discussed a variety of other terrorist plots with other members of his Al Qaeda cell, including crashing planes into targets in America, killing members of Congress, and blowing up American military aircraft.