A State Department memo that has caught the attention of prosecutors describes a CIA officer's role in sending her husband to Africa and disputes administration claims that Iraq was shopping for uranium (search), a retired department official said Tuesday.

The classified memo was sent to Air Force One just after former U.S. Ambassador Joseph Wilson (search) went public with his assertions that the Bush administration overstated the evidence that Iraq was interested in obtaining uranium from Niger for nuclear weapons.

The memo has become a key piece of evidence in the CIA leak investigation (search) because it could have been the way someone in the White House learned — and then leaked — the information that Wilson's wife worked for the CIA and played a role in sending him on the mission.

The document was prepared in June 2003 at the direction of Carl W. Ford Jr., then head of the State Department's bureau of intelligence and research, for Marc Grossman, the retired official said. Grossman was the Undersecretary of State who was in charge of the department while Secretary Colin Powell (search) and his deputy, Richard Armitage, were traveling. Grossman needed the memo because he was dealing with other issues and was not familiar with the subject, the former official said.

"It wasn't a Wilson-Wilson wife memo," said the official, who spoke on condition of anonymity because the investigation is still under way. "It was a memo on uranium in Niger and focused principally on our disagreement" with the White House.

Armitage called Ford after Wilson's op-ed piece in The New York Times and his TV appearance on July 6, 2003 in which he challenged the White House's claim that Iraq had purchased uranium yellowcake from Niger.

Armitage asked that Powell, who was traveling to Africa with Bush, be given an account of the Wilson trip, said the former official.

The original June 2003 memo was readdressed to Powell and included a short summary prepared by an analyst who was at a 2002 CIA meeting where Wilson's trip was arranged and was sent in one piece to Powell on Air Force One the next day.

The memo said Wilson's wife worked for the CIA and suggested her husband go to Niger because he had contacts there and had served as an American diplomat in Africa. However, the official said the memo did not say she worked undercover for the spy agency nor did it identify her as Valerie Plame, which was her maiden name and cover name at the CIA.

Her identity as Plame was disclosed first by columnist Robert Novak and then by Time magazine reporter Matt Cooper. The leak investigation by special counsel Patrick Fitzgerald is looking into who in the Bush administration leaked Plame's identity to reporters and whether any laws were broken.

A 1982 law prohibits the deliberate exposure of the identity of an undercover CIA officer.

Wilson believes the Bush administration leaked the name as retribution for his criticism.

President Bush said Monday he would fire any member of his staff who "committed a crime," a change from his previous vow to fire anyone involved in the leak.

The past two weeks have brought revelations that top presidential aide Karl Rove was involved in leaking the identity of Plame to Novak and to Cooper.

The former State Department official stressed the memo focused on Wilson's trip and the State Department intelligence bureau's disagreement with the White House's claim about Iraq trying to get nuclear material. He said the fact that the CIA officer and Wilson were husband and wife was largely an incidental reference.

The June 2003 memo had not gone higher than Grossman until Wilson's op-ed column for The New York Times headlined "What I Didn't Find In Africa" and his TV appearance to dispute the administration. Wilson's article asked the question: "Did the Bush administration manipulate intelligence about Saddam Hussein's weapons programs to justify an invasion?"