• What started the CIA leak probe?On July 6, 2003, former diplomat Joseph C Wilson IV went public with his conclusion that it was highly doubtful that Saddam Hussein had sought uranium from Niger for a weapons of mass destruction programme. That called into question one of the central claims made by the Bush administration prior to the invasion of Iraq.Eight days later, columnist Robert Novak wrote that “two senior administration officials” told him Wilson had been suggested for the trip by his wife, identified as Valerie Plame, a “CIA operative on weapons of mass destruction.”In December 2003, US Attorney Patrick J Fitzgerald in Chicago was named as a special counsel to investigate whether the identification of Plame, who was an undercover CIA officer, was a violation of federal law.• Who is Libby?I Lewis “Scooter” Libby, chief of staff to US Vice-President Richard Cheney, has been convicted on charges of obstruction of justice and perjury. He is alleged to have lied during interviews with FBI investigators and during sworn appearances before the grand jury. In his testimony, Libby said he had heard about Plame from Tim Russert of NBC, and merely passed on the information as unsubstantiated gossip to other reporters. But Russert later denied having given him the information. Cheney is reported to have been one of the officials who provided information about Plame to Libby. Libby is alleged to have then passed on the information to reporters.• What was media’s role? In addition to Novak, six other journalists are reported to have known Plame’s identity before the column was published, including Judith Miller, then with the New York Times. Jailed for 85 days after refusing to testify about her source before the grand jury, Miller eventually testified that Libby talked to her about Plame on three occasions before the Novak column.Fitzgerald’s wide-ranging, 22-month probe included interviews with Bush, Cheney, Rove, Libby, and journalists like Miller and Matthew Cooper of Time magazine. Fitzgerald told the court a year ago that his investigation was largely complete except for testimony he was seeking from Cooper and Miller. Much of the last year has involved highly public battles between the prosecutor and journalists. Glenn Kessler and Walter Pincus of The Washington Post and NBC’s Tim Russert agreed to limited questioning by Fitzgerald’s investigators after receiving waivers from their sources. Cooper testified before the grand jury after receiving a similar waiver. Novak has refused to comment in detail on his role.• What happens next?Libby must still be arraigned and possibly face trial or negotiate the terms of a plea agreement. Fitzgerald has said the probe will continue. Karl Rove, US President George Bush’s chief political advisor, remains under investigation.