Osama bin Laden’s son-in-law said he heard about a major act being organized before the Sept. 11 attacks, according to an FBI agent.

Special agent Michael Butsch revealed the claim Thursday during Sulaiman Abu Ghaith's trial in New York, according to The Associated Press

“Something big was going to happen,” Butsch recounted Ghaith as saying after he was captured by the United States a year ago in Jordan.

The former al Qaeda spokesman told Butsch he heard about something major being planned during a visit to al Qaeda training camps in Afghanistan in the summer of 2001. He said he did not, however, know of a specific plan to attack the U.S. 

While the Justice Department doesn’t believe Ghaith was involved in the Sept. 11 attacks, he was charged last March with conspiring to kill Americans and providing support to al Qaeda. Ghaith has pleaded not guilty and is the most senior al Qaeda official since Sept. 11 to face trial on U.S. soil. 

He was married to bin Laden’s daughter Fatima.