Osama bin Laden's son-in-law Suleiman Abu Ghaith took the stand in his own defense Wednesday and portrayed himself as a mere mouthpiece of the al Qaeda boss who was tapped to "deliver the message" within hours of the Sept. 11 terror attacks.
But on cross-examination, Abu Ghaith conceded that he did believe the message the al Qaeda boss was sending.
Prosecutors say Abu Ghaith — on trial in Manhattan Federal Court — knew of planned attacks against the U.S. and provided support and resources to terrorists, but he denies it.
With anonymous jurors listening raptly after the surprise announcement that he would testify, Abu Ghaith recounted how bin Laden recruited him in June 2001 to speak to the men at his training camps, according to the Associated Press.
Three months later, on the night of 9/11, he was summoned to a cave to meet with bin Laden, who asked him: "Did you learn what happened? We are the ones who did it."
"I want to deliver a message to the world. ... I want you to deliver the message," bin Laden said, according to Abu Ghaith.
He said the videos he made were based on talking points by bin Laden, religious in nature and meant to inspire Muslims to rise up against oppression.
Prosecutor Michael Ferrara elicited from Abu Ghaith that bin Laden gave him four or five points to make in his first videotaped message. Then he played the lengthy video for the jury, suggesting the defendant's words went beyond what bin Laden scripted.
Earlier, Abu Ghaith said before he first met bin Laden, he knew he was suspected in terrorist attacks but still "wanted to get to know that person."
"I wanted to see what he had, what is it he wanted," he said.
Abu Ghaith faces life in prison if convicted.
His decision to testify came as a surprise and followed a judge's ruling that Khalid Sheikh Mohammed, the accused mastermind of the Sept. 11 attacks, would not take the stand. He apparently was ready to say that Abu Ghaith had no operational knowledge of al Qaeda plans.
NBC News' Susan Kroll and the Associated Press and Reuters contributed to this report.