New York (CNN) -- As several thousand Muslim men and boys lay in mass graves in Srebrenica, Bosnia, a young boy -- maybe 12 -- wearing camouflage and clutching a Kalashnikov received a hug from a grieving mother.
"I wish I trained my son," the woman said.
Abu Hamza al-Masri broke down in the tears on the stand Thursday as he recounted the moment, which was pivotal for the radical cleric. He left Bosnia with the belief that training in physical jihad, even for children, is crucial to the defense of Muslims when governments and outside forces fail to keep them safe.
He's seen it from Afghanistan to Chechnya, he said: "The West will not do the job."
The Egyptian-born cleric pleaded not guilty to 11 counts of terrorism-related charges in 2012. He was extradited to the United States after a lengthy legal battle.
The charges against him involve giving aid to terrorist groups, including supporting efforts to establish an Islamic jihad training camp in rural Oregon; sending a young recruit from London to fight alongside al Qaeda on the front lines in Afghanistan; and helping kidnappers in Yemen with the 1998 abduction of a tour group.
Al-Masri, who may be the only defense witness, testified he came to London as a young man because loved the Western lifestyle, wanted to make money and have fun. "American style," he smiled.
He worked as a bouncer and strip-club manager before bits of Islamic teachings from friends began to penetrate his mind, he testified. The hypocrisy of his lifestyle hit him like a slap in the face.
Al-Masri would go on to become the high-profile imam of a London mosque and allegedly inspired several notorious terrorists with his sermons, including failed shoe bomber Richard Reid and 9/11 hijacker Mohammed Atta.
He denied on the stand that he ever provided support to al Qaeda or the Taliban government.
He noted that he hasn't spoken before a crowd since his 2004 arrest and that a decade in solitary confinement has eroded his memory and grasp of language. The trial has been reinvigorating, said al-Masri, and the preacher drew laughter from in the courtroom Wednesday afternoon as he used examples of marital spats to illustrate the practical application of Islamic truth.
The government's three-week case against al-Masri was an effort to connect the dots between the defendant and events thousands of miles away from him, through key witnesses who often had never met him, and are testifying as government informants in exchange for leniency or protection.
"He was a trainer, a terrorist, and he used the cover of religion so he could hide in plain sight in London," said Assistant U.S. Attorney Edward Kim in his opening statement.
Weapons and gas masks were found at al-Masri's London mosque, the prosecutor said: "Tools of war stockpiled in a place of worship."
Defense lawyer Joshua Dratel told the jury in his opening statement that no evidence links the cleric to the alleged crimes -- "not in Yemen, not in Oregon, not in Afghanistan."
Dratel said his client "never gave directions or orders to people" and served merely as a "commenter on events and issues" when he lauded the late al Qaeda leader Osama bin Laden and celebrated the September 11, 2001, terrorist attacks.
"These are ideas, not acts," he said. "These are expressions, not crimes."
Missing both hands, Al-Masri wears an occasional writing prosthesis on his right forearm rather than the infamous hook-like device he's often seen sporting in photographs. During his testimony, he said colorful stories abound about how he lost the limbs. It happened, he testified, when he worked as an engineer with the Pakistani military during the rebuilding of war-torn Afghanistan, and a bottle-bomb intended for a roadblock project exploded in his hands.
Al-Masri, who faces the possibility of life in prison if convicted, will continue his testimony Monday.