Documents in a US investigation into the leaking of a CIA officer's name to the media indicate the vice-president's chief of staff first heard of the covert CIA officer from Dick Cheney, the New York Timesreported today.
The newspaper said notes of a previously undisclosed conversation between Lewis "Scooter" Libby and Mr Cheney appear to differ from Mr Libby's grand jury testimony that he first heard the name of Valerie Plame from journalists.
Mr Cheney's office has increasingly become the focus of an investigation which is trying to establish whether Ms Plame's identity was leaked in an effort to discredit her husband, former ambassador Joseph Wilson.
Mr Wilson exposed as false the administration's claim before the Iraq war that Saddam Hussein had tried to import nuclear weapons materials from Niger.
Special prosecutor Patrick Fitzgerald is expected to decide this week whether to seek criminal indictments in the case.
Lawyers involved in the case have said Mr Libby and Karl Rove, President Bush's senior adviser, both face the possibility of indictment.
Mr Fitzgerald questioned Cheney over a year ago. It is not publicly known what the vice president told the prosecutor.
Mr Cheney has said little in public about what he knew. In September 2003, he told NBC he did not know Mr Wilson or who sent him on a trip to Niger in 2002 to check into a intelligence - later deemed unreliable - that Iraq may have been seeking to buy uranium there.