Al Qosi claimed they were strapped to the floor in an interrogations center known as the Hell Room, wrapped in Israeli flags, taunted by female interrogators who rubbed their bodies against them in sexually suggestive ways, and left alone in refrigerated cells for hours with deafening music blaring in their ears. Back then, Pentagon officials dismissed Al Qosi's allegations as the fictional rantings of a hard-core terrorist.

But in recent weeks a stack of declassified government documents has given new credence to many of the claims of abuse at Guantanamo. The documents are also raising fresh questions about the Bush administration's handling of detainees at a time when a prime architect of that policy, White House counsel Alberto Gonzales, is facing a Senate confirmation vote as the president's nominee to be attorney general.

Many of the documents come from an unexpected source: the FBI. As part of a Freedom of Information Act lawsuit brought by the American Civil Liberties Union, the bureau has released internal e-mails and correspondence recording what their own agents witnessed at Gitmo. Coupled with accounts from other agencies such as the Defense Intelligence Agency—also released as part of the FOIA lawsuit—the FBI reports amount to a powerful case that many of the scenes alleged by Al Qosi and other Gitmo detainees may actually have happened. (Al Qosi is still in Gitmo, facing charges before a military tribunal.) And the reports suggest that the interrogation scandal is not going away any time soon, even if Gonzales is confirmed, as expected.

Many of the FBI accounts came from conscience-stricken agents troubled by what they had witnessed. One agent reported seeing a detainee sitting on the floor of an interrogation cell with an Israeli flag draped around him while he was bombarded by loud music and a strobe light—almost exactly what Al Qosi had alleged. Another reported seeing detainees chained hand and foot in fetal positions, in barren cells with no chair, food or water.

In one account that seemed to parallel the sickening scenes from Abu Ghraib Prison in Iraq, an FBI agent reported the way in which a female U.S. Army sergeant sexually humiliated a shackled male prisoner during Ramadan and even "grabbed his genitals."

Pentagon officials acknowledge that, frustrated by detainees' refusal to talk, Secretary of Defense Donald Rumsfeld had approved "aggressive" interrogation techniques to be used at Gitmo. But last week, stunned by the new disclosures, Gen. Bantz Craddock, chief of the U.S. Southern Command—which runs Gitmo—ordered a full-scale inquiry into the FBI agents' allegations, which appear to go far beyond anything authorized. Craddock wants to know why allegations from seemingly credible government agents had not come to the U.S. military's attention sooner.

After hearing of the FBI memos, NEWSWEEK has learned, Sens. Dianne Feinstein and Patrick Leahy fired off angry letters to FBI Director Robert Mueller demanding to know why he failed to disclose his own agents' complaints when they questioned him about Gitmo in a hearing last May. Feinstein last week called Mueller's evasive answers at the time "gobbledygook." When her comment was reported on NEWSWEEK's Web site, Mueller called Feinstein to express regret that he hadn't kept her better informed. As the inquiries continue, he may not be the only U.S. government official who has further explaining to do.