US Vice-President Dick Cheney could be called to testify in the CIA leak case involving his former chief of staff, a US prosecutor said in a pre-trial filing made on Wednesday.

Special Counsel Patrick Fitzgerald told a federal court that 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.

Fitzgerald was referring to a July 6, 2003, article written by Plame's husband, Bush administration critic and former US Ambassador Joseph Wilson.

Shortly after the article appeared, Plame's identity as a covert CIA operative was leaked to journalists. Fitzgerald is investigating whether Bush administration officials broke the law by disclosing 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," Fitzgerald said.

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.

Fitzgerald said understanding what conversations took place between Cheney and Libby in the week after Wilson's opinion piece was published was critical to determining whether Libby thought it was necessary or appropriate to disclose Wilson's wife's CIA status with reporters.

Cheney, whose name has surfaced in other court documents as well, told the Fox News Channel in February that he may be called as a witness in the case.

In the court filing, Fitzgerald said Libby has acknowledged that he and the vice-president discussed Wilson's article. "Here as defendant has acknowledged, the vice-president communicated to defendant the facts he considered notable, and also directed defendant to get out to the public 'all' the facts in response to the Wilson Op Ed," Fitzgerald wrote in the court filing.

"The state of mind of the vice-president as communicated to defendant is directly relevant to the issue of whether defendant knowingly made false statements to federal agents and the grand jury regarding when and how he learned about Ms Wilson's employment and what he said to reporters regarding this issue," Fitzgerald said in the court filing.

Source: China Daily