A Moroccan prisoner released from Guantanamo in 2004 was Osama bin Laden's top bodyguard, according to testimony Thursday in the war crimes trial of another alleged bodyguard.

Defendant Salim Hamdan said the Moroccan, Abdellah Tabarak, was head of the al-Qaida chief's security detail, said Naval Criminal Investigative Service agent Michael St. Ours, relating what Hamdan told him in a 2002 interrogation.

St. Ours, who also questioned Tabarak at Guantanamo, said he was surprised to learn from Hamdan's lawyers that the Moroccan had been released because he was a "very hard individual."

Tabarak _ Hamdan's reputed boss _ was one of five Guantanamo prisoners returned to Morocco in August 2004. At the time, he was suspected of having served as a bodyguard for the al-Qaida leader in Sudan and Afghanistan.

Army Col. Steve David, chief defense counsel for the Guantanamo tribunals, said several men suspected of more serious crimes than Hamdan have been released from the military prison at the U.S. Navy base in southeast Cuba.

"That's the nature of the beast," he said. "Do we like it? No."

The U.S. military does not comment on decisions to release individual detainees.

Hamdan, a Yemeni, has been held at Guantanamo since May 2002. He is accused of transporting weapons for al-Qaida and helping bin Laden to escape U.S. retribution after the Sept. 11 attacks by helping him avoid being detected in Afghanistan.

He faces a maximum life sentence if convicted of conspiracy and supporting terrorism.