US Vice President Dick Cheney could be called to testify in the CIA leak case involving his former chief of staff, a US prosecutor has said.
Special Counsel Patrick Fitzgerald told a federal court that Mr Cheney's hand-written notes on a newspaper article referring to Valerie Plame shortly before she was exposed as a CIA operative were uniquely relevant to the issues in the case.
Mr Fitzgerald was referring to a July 6th, 2003, article written by Ms Plame's husband, former US ambassador and Bush administration critic Joseph Wilson.
Shortly after the article appeared, Mr Plame's identity as a covert CIA operative was leaked to journalists.
Mr Fitzgerald is investigating whether Bush administration officials broke the law by disclosing Mr Plame's identity. "At the time, the vice president, rather than other potential witnesses, was upset that his personal credibility had been attacked unfairly in his view," Mr Fitzgerald said.
Mr Cheney's former aide, Lewis "Scooter" Libby was charged with obstruction of justice and lying to FBI agents and a grand jury during the investigation. He has pleaded not guilty and is scheduled to go to trial in January.
Mr Fitzgerald said understanding what conversations took place between Mr Cheney and Mr Libby in the week after the opinion piece was published was critical to determining whether Mr Libby thought it was necessary or appropriate to disclose Mr Wilson's wife's CIA status with reporters.