"Because it was the biggest charity, [the commission] helped the mujaheddin the most," Hamad said, adding that it had provided "everything a person needed to exist."
Hamad, 37, is expected to be called as a witness in a lawsuit filed by Cozen O'Connor alleging that Saudi Arabia and affiliated charities financed al-Qaeda and other groups as they geared up for the 9/11 attacks.
As a convicted terrorist, Hamad is an imperfect witness.
During the Balkans war, from 1992 to 1995, jihadists from North Africa and the Middle East were accused of atrocities against indigenous Serbs and Croatians.
Hamad admits having done "bad things" as an al-Qaeda fighter, and he is serving a 10-year sentence in a Bosnian jail for his role in a 1997 Mostar bombing.
Yet Hamad's account of his time in the Balkans went largely uncontroverted during the U.N. trial, where he was a prosecution witness.
He contends that the Saudi High Commission, an agency of the Saudi government, and other Islamist charities supported al-Qaeda-led units that committed atrocities. Mujaheddin units, he said, recruited fighters, prepared for battle, and financed their operations in the Balkans.
He said the Saudi High Commission had poured tens of millions of dollars into mujaheddin units led by al-Qaeda operatives who fought with Osama bin Laden in Afghanistan.
Money intended for humanitarian relief bought weapons and other military supplies.
The charities also provided false identification, employment papers, diplomatic plates and vehicles that permitted Islamist fighters to enter the country and pass easily through military checkpoints, Hamad said.
Several charity offices, including those of the Saudi High Commission, were led by former mujaheddin or al-Qaeda members, at least one of whom trained with Hamad in an al-Qaeda camp in Afghanistan, he said.
Like other al-Qaeda fighters, Hamad said, he was an employee of the Saudi High Commission for a time and traveled through the war zone in commission vehicles with diplomatic plates.
Contact staff writer Chris Mondics at 215-854-5957 or firstname.lastname@example.org