The Iraqi informant known as “Curve Ball” – whose fake story about Saddam Hussein’s alleged weapons of mass destruction program helped build the case for the US-led invasion of Iraq – has been identified by the CBS 60 Minutes Program.

Rafid Ahmed Alwan first arrived in Germany as a refugee in 1999 and told authorities he had been a chemical engineer who managed a biological weapons factory, Djerf al-Nadaf, in Iraq.

Apparently, Mr Alwan told this story to increase his chances of being granted asylum in Germany. He further embellished the story when he told German officials that a dozen of his co-workers had died manufacturing biological weapons.

German intelligence officers sent summaries of Mr Alwan’s debriefings to the US but warned that they doubted his story. Firstly, they said they could not verify the information; secondly, Mr Alwan suffered from mental and emotional problems.

One interrogator’s report stated, “He is not a psychologically stable guy,” while a psychological assessment concluded that “He is not a completely normal person.”

Nevertheless, then-CIA director George Tenet said he believed the story told by “Curve Ball” and tried without success to get the story verified.

Soon after, then-Secretary of State Colin Powell used the information as the basis of his speech to the United Nations in which he laid out the US argument for invading Iraq.

Planning for the invasion continued despite the report of UN weapons inspectors, who examined the Djerf al-Nadaf plant and confirmed that it contained no biological agents.

German intelligence officials also said that the Bush administration and the CIA exaggerated Mr Alwan’s claims of Iraq’s weapons of mass destruction in the lead up to the invasion.

After a two-year investigation, CBS also discovered that “Curve Ball” had never been a chemical engineer, although he had worked in a chemical weapons factory briefly. After a relatively short stint as a mediocre university student, he had gone to work for a Baghdad television company whose management accused him of theft.

He then sought asylum in Germany, where it is believed he still lives.

CIA senior official Tyler Drumheller told 60 Minutes, “It was a guy trying to get his green card essentially, in Germany, and playing the system for what it was worth.”

The 60 Minutes program is due to be broadcast on Sunday.