The Iraqi defector whose claims regarding Saddam Hussein's biological warfare capabilities were central to the US government's case for the 2003 invasion, despite repeated warnings that they were dubious, has been unmasked by a television documentary.
The informer, codenamed Curveball was Rafid Ahmed Alwan who, in 1999, turned up at a refugee centre in Germany seeking political asylum. He went on to convince the Pentagon he was a brilliant chemist who had helped develop mobile biological warfare laboratories.
His role in the build-up to war was exposed in a detailed investigation by the Los Angeles Times, in which he was dismissed as an "out-and-out" fabricator who should have aroused scepticism in the CIA. The LA Times said Curveball was the brother of a senior aide to Ahmed Chalabi, then leader of the Iraqi National Congress, and reported that neither the Pentagon nor the CIA knew exactly who he was.
But he is named for the first time in an edition of the US network CBS's documentary 60 Minutes to be broadcast tomorrow. The report is already on the programme's web pages. The documentary assumes he is still living in Germany, under a false name.
Mr Alwan claimed to have been a highly-regarded chemical engineer working on the production of mobile biological weapons at a plant in Djerf al-Nadaf.
Curveball's claims were discredited in 2002 by senior officials in the German intelligence service, the BND, who wrote to the CIA warning his account was vague, second-hand and impossible to check. They also thought he was psychologically unstable.
But, in January 2003, President Bush told Curveball's story in his State of the Union address and it was repeated by the Secretary of State Colin Powell a month later when he put the US the case for invasion before the UN.
The senior BND officer in charge of the case later spoke of his horror as he heard Mr Powell exaggerate Curveball's tale. "We had always told them it was not proven. It was not hard evidence," he said.
In January 2004, Vice-President Dick Cheney was maintaining that discovery of the germ warfare labs would provide "conclusive" proof that Iraq had developed WMDs. But US investigators sent into Iraq after the invasion to find evidence of WMDs uncovered Curveball's file in Baghdad. In his late 20s when he arrived in Germany, he had been a low-level trainee engineer and not the project chief as the CIA had claimed.
He had been sacked in 1995, which was when he claimed to have started work on the mobile germ labs. He had also been jailed for a sex offence and had worked as a Baghdad taxi driver. His marks for his university course in chemical engineering were low.
The information was passed to Mr Powell by the CIA director George Tenet, who, in the documentary, denies ever having seen the German letter. A former senior official in the CIA, Tyler Drumheller, tells 60 Minutes: "It was a guy trying to get his green card essentially, in Germany, and playing the system for what it was worth."