GUANTANAMO BAY NAVY BASE, Cuba -- A Navy criminal investigation has concluded that a Yemeni man found dead in the Guantánamo prison camps' psychiatric ward in June committed suicide, the detention center commander said Tuesday.

Navy Rear Adm. Tom Copeman declined to specify the method but said Mohammed Abdullah Saleh, 31, ``unfortunately but successfully committed suicide'' inside the prison camp's 12-cell Behavioral Health Unit on June 1.

The Yemeni had been described at the time as a long-committed hunger striker who had been held at this remote detention center since early 2002 on suspicion of ties to the Taliban.

The death had been listed as an ``apparent suicide'' soon after prison camp staff discovered him ``unresponsive and not breathing.'' Different accounts attributed the cause of death, alternately, to asphyxiation and a drug overdose. Saleh's body was returned to Yemen for burial the same week, after an autopsy.

The Naval Criminal Investigative Service forwarded its findings to Air Force Gen. Douglas Fraser, the commander of the U.S. Southern Command in Miami, which supervises the prison camps where five detainees have reportedly killed themselves since June 2006.

Copeman said the episode prompted changes ``procedurally, to process and training'' that would ``hopefully lower the risk'' of a similar episode.

The detention center detainee census was at 223 on Tuesday, with Obama administration sources reporting that several captives already cleared for release would soon be sent overseas for resettlement in undisclosed nations.

In June 2006, three detainees committed suicide by hanging themselves simultaneously inside three nearby cells in Camp 1, a startling episode that led to a sweeping review of cell block procedures that now require guards to keep constant watch on each of the detainees.

A fourth detainee was found dead the next year in Camp 5 in an apparent suicide that was still under investigation, said Navy Lt. Cmdr. Brook DeWalt, a Guantánamo spokesman. A senior camp officer said at the time that detainee hanged himself also.

Separately, Copeman said Tuesday that he was aware of a federal judge's order to release videotapes from November 2002 that gave a window into the harsh Guantánamo interrogation of a Saudi detainee, Mohammed Qahtani, whose treatment was considered ``torture'' by a senior Pentagon official.

Copeman said, however, that detention center staff had searched their records and found no evidence that the Department of Defense was in possession of those interrogation videos.

``I'm not saying they don't exist,'' the admiral said. ``I'm just saying to the best of our knowledge down here, based on the time we've had to look into it, there's nothing in our history files that indicates we've ever seen then, taken them or had them in our possession.''

The Convening Authority for Military Commissions, Susan Crawford, told The Washington Post's Bob Woodward in January that a special interrogation program, authorized by Defense Secretary Donald Rumsfeld, made it impossible to proceed with a war crimes prosecution against Qahtani, now 30, based on his confessions.

The Saudi's interrogation took place over 50 days from November 2002 to January 2003, though he was held in isolation until April 2003 on suspicion he was meant to be the 20th hijacker in the Sept, 11, 2001, terror attacks.

Interrogators here menaced him with dogs, forced him to wear a bra, and put him on a leash and ordered him to bark as part of a program meant to break his will, according to a leaked interrogation log.

``For 160 days his only contact was with the interrogators,'' Crawford told Woodward. ``Forty-eight of 54 consecutive days of 18- to 20-hour interrogations. Standing naked in front of a female agent. Subject to strip searches. And insults to his mother and sister.''

``His treatment met the legal definition of torture,'' she told The Post. ``And that's why I did not refer the case'' for prosecution.

Attorneys have for years sparred with the Pentagon and U.S. intelligence agencies over whether there are hidden, classified videotapes of detainee interrogations carried out in the aftermath of the 9/11 terrorist attacks. Guantánamo detainees have consistently told their lawyers that the military videotaped their interrogations, and prison camp commanders have consistently denied it.

Separately, the CIA acknowledged that it destroyed tapes of some overseas interrogations of alleged senior al Qaeda captives who were waterboarded and are now held here facing war crimes prosecution.