Sometimes the music was American rap, sometimes Arab folk songs. In the CIA prison in Afghanistan, it came blaring through the speakers 24 hours a day. Prisoners held alone inside barbed-wire cages could only speak to each other and exchange their news when the music stopped: if the tape was changed or the generators broke down. In one such six-foot-by-10-foot cell in February 2004, equipped with a low mattress and a bucket as a toilet, sat a man in shackles named Ibn al Sheikh al Libi, the former al Qaeda camp commander described by former CIA director George Tenet in his autobiography last year as "the highest ranking al-Qa’ida member in U.S. custody" just after 9/11. In this secret facility known to prisoners as "The Hangar" and believed to be at Bagram Air Base north of Kabul, al Libi told fellow "ghost prisoners," one recalled to me for a PBS "Frontline" to be broadcast tonight, an incredible story of his treatment over the previous two years: of how questioned at first by Americans, by the FBI and then CIA, of how he was threatened with torture. And then how he was rendered to a jail cell in Egypt where the threats became a reality. In his book, officially cleared for publication, Tenet confirms how the CIA outsourced al Libi’s interrogation. He said he was sent to a third country (inadvertently named in another part of the book as Egypt) for "further debriefing." The Bush administration has said that terrorists are trained to invent tales of torture. Click Here for Full Blotter Coverage. Yet, on this occasion, the CIA believed al Libi’s tales of torture — an account that has proved to be one of the most serious indictments of the agency’s practice of extraordinary rendition: sending suspected Islamic terrorists into the hands of foreign jailers without legal process. In a CIA sub-station close to al Libi’s jail cell, the CIA’s "debriefers," who had been talking to al Libi for days after his return from Cairo, were typing out a series of operational cables to be sent Feb. 4 and Feb. 5 to the CIA Headquarters in Langley, Va. In the view of some insiders, these cables provide the "smoking gun" on the whole rendition program — a convincing account of how the rendition program was, they say, illegally sending prisoners into the hands of torturers. Under torture after his rendition to Egypt, al Libi had provided a confession of how Saddam Hussein had been training al Qaeda in chemical weapons. This evidence was used by Colin Powell at the United Nations a year earlier (February 2003) to justify the war in Iraq. ("I can trace the story of a senior terrorist operative telling how Iraq provided training in these [chemical and biological] weapons to al Qaeda," Powell said. "Fortunately, this operative is now detained, and he has told his story.") But now, hearing how the information was obtained, the CIA was soon to retract all this intelligence. A Feb. 5 cable records that al Libi was told by a "foreign government service" (Egypt) that: "the next topic was al-Qa’ida’s connections with Iraq…This was a subject about which he said he knew nothing and had difficulty even coming up with a story." Al Libi indicated that his interrogators did not like his responses and then "placed him in a small box approximately 50cm X 50cm [20 inches x 20 inches]." He claimed he was held in the box for approximately 17 hours. When he was let out of the box, al Libi claims that he was given a last opportunity to "tell the truth." When al Libi did not satisfy the interrogator, al Libi claimed that "he was knocked over with an arm thrust across his chest and he fell on his back." Al Libi told CIA debriefers that he then "was punched for 15 minutes." (Sourced to CIA cable, Feb. 5, 2004). Here was a cable then that informed Washington that one of the key pieces of evidence for the Iraq war — the al Qaeda/Iraq link — was not only false but extracted by effectively burying a prisoner alive. Although there have been claims about torture inflicted on those rendered by the CIA to countries like Egypt, Syria, Morocco and Uzbekistan, this is the first clear example of such torture detailed in an official government document. The information came almost one year before the president and other administration members first began to confirm the existence of the CIA rendition program, assuring the nation that "torture is never acceptable, nor do we hand over people to countries that do torture." (New York Times, Jan. 28, 2005) Last September, these red-hot CIA cables were declassified and published by the Senate Intelligence Committee, but in, a welter of other news, one of the most important documents in the history of rendition had passed almost without notice by the media. As far as I can tell, not a single newspaper reported details of the cable. (Senate Intelligence Committee, page 81, paragraph 2) A spokesman of the intelligence committee told me last month: "We were not able to establish definitively who was told about the cable or its contents or who read it." Other members of Congress may soon be taking up this story to find out just who at the White House was told about the cable. Meanwhile, al Libi, who told fellow prisoners in Bagram he was returned to U.S. custody from Egypt on Nov. 22, 2003, has disappeared. He was not among the "high-value prisoners" transferred to Guantanamo last year. *Stephen Grey is the reporter for the documentary "Extraordinary Rendition" that was broadcast on Frontline/World, Tuesday, Nov. 6 on PBS. He is the author of "Ghost Plane: The True Story of the CIA’s Rendition and Torture Program" (St Martin’s Press). He is an award-winning investigative reporter who has contributed to the New York Times, BBC, PBS and ABC News among others.