A declassified document, meanwhile, tells of beatings and other abuse at the same Baghdad airport detention complex.

Between eight and 12 "high-value detainees" at the airport's Camp Cropper fit the weapons-scientist category, according to the U.S. command in Baghdad. They're known to include Amer al-Saadi, Iraq's liaison to U.N. inspectors in 2002-03, and Rihab Rashid Taha, a biological weapons expert of the 1980s.

All are believed to have been held for more than two years, and are still held, largely incommunicado, nine months after Charles A. Duelfer's U.S. arms hunters declared that the Iraqis had no programs to build weapons of mass destruction and had destroyed their previous banned arms in 1991.

Ex-chief inspector David Kay pointed out that in a later final note Duelfer urged the detained scientists be freed.

"I absolutely agree with his interpretation, that in terms of WMD reasons there's no reason for continued detention," Kay said in an interview. "Whatever they knew about WMD, we now know."

Ex-inspector Rod Barton, an Australian biologist who was a key deputy to Duelfer, said it's "outrageous" that the Iraqis are still held, and cited the example of Huda Salih Mahdi Ammash, a bioweapons specialist in the 1980s.

"Huda is there accused of restarting the bioweapons program in the mid-1990s. And there was no such program," he said.

For the past year, the U.S. military has declined to discuss why the scientists are still held, saying that although they remain physically in U.S. custody, their legal status would be determined by the Iraqi Special Tribunal, which is preparing to prosecute members of the ousted Baathist regime.

No criminal charges have been announced against the former arms experts, however, and AP telephone calls and e-mail queries to the tribunal went unanswered.

The U.S. military also has been largely silent about the death of Mohammad Munim al-Izmerly, 65, a former chemical weapons specialist who was held at Camp Cropper and whose body was delivered to a Baghdad hospital on Feb. 17, 2004, along with a death certificate claiming he had died of natural causes 17 days earlier.

The certificate cited "brainstem compression," without saying what caused it. Al-Izmerly's family arranged for an Iraqi autopsy, which found he died of blunt trauma injury, a blow to the head.

The U.S. Baghdad command last year would not answer reporters' questions about the death. When the AP inquired this March, however, the Army's Criminal Investigation Command said an investigation had been "reopened."

Asked this week for an update, the Army would not discuss what progress, if any, had been made in the case. "We have not charged anyone," said Lt. Col. Pamela Hart, an Army spokeswoman at the Pentagon.

In another case at the same complex's Temporary Detention Facility, interrogators from the Defense Intelligence Agency witnessed the beating of a prisoner by U.S. special forces and saw burn marks and bruises on other detainees, according to a declassified Pentagon document dated June 25, 2004.

One interrogator took photographs of the first prisoner's injuries, but a special forces supervisor confiscated them, according to the memo, which was released to the American Civil Liberties Union under the Freedom of Information Act. The two interrogators involved said they also were threatened, ordered not to leave the compound, and had their vehicle keys confiscated.

The Pentagon says four special forces members were subsequently punished in that case.

It is not known whether chemist al-Izmerly suffered his fatal injury at Camp Cropper or at this associated transient facility, which Barton said was reputed to be a place where detainees were "softened up."

"I doubt whether it occurred at Cropper itself -- it would be too `public,'" said the ex-inspector, who said he was told in Baghdad at the time that al-Izmerly died of a brain tumor.

Kay said al-Izmerly had been cooperative with his interrogators in 2003, adding to the mystery of why the chemist might have been beaten. Kay left Baghdad before the Iraqi died.