The Iraqi defector whose claims that Saddam Hussein's government had biological weapons became part of the Bush administration's justification for the 2003 invasion of Iraq has admitted that he fabricated his story. The defector, Rafid Ahmed Alwan al-Janabi, who was code-named Curveball" by the Central Intelligence Agency and German intelligence officials, told the British newspaper The Guardian on [February 15] that he had concocted his tale that Iraq was hiding mobile bioweapons laboratories. The strange case of "Curveball" has become one of the most infamous episodes in the Bush administration's case for war. Mr. Janabi's claim about the mobile laboratories was featured prominently in Secretary of State Colin L. Powell's address to the United Nations in February 2003, when he laid out the administration's case that Mr. Hussein was hiding weapons of mass destruction. The United States invaded Iraq in March 2003, and eventually determined that Iraq did not have any such weapons. It later became clear that the Bush administration had relied heavily on bogus information from unreliable exiles like Mr. Janabi.