A classified State Department memo with information about CIA officer Valerie Plame was marked (S) for “Secret,” a warning to any Bush administration official who read it that the information was classified.

Plame — referred to by her married name, Valerie Wilson  — is mentioned in the second paragraph of the three-page document, which was written on June 10, 2003, by an analyst in the State Department’s Bureau of Intelligence and Research (INR).

The paragraph identifying her as the wife of former ambassador Joseph C. Wilson IV was clearly marked to show that it contained classified material at the “secret” level. The CIA classifies as “secret” the names of officers whose identities are covert, senior agency officials confirm.

Anyone reading that paragraph would have been aware that it contained secret information. It is a federal crime, punishable by up to 10 years in prison, for a federal official to knowingly disclose the identity of a covert CIA official if the person knows the government is trying to keep it secret.

Prosecutors attempting to determine whether senior government officials knowingly leaked Plame’s identity as a covert CIA operative to the media are investigating whether White House officials gained access to information about her from the memo, the Washington Post reported in today’s editions.

The memo may answer three central questions in the Plame case: Who in the Bush administration knew about Plame’s CIA role? Did they know the agency was trying to protect her identity? And, who leaked it to the media?

The memo describes why State Department intelligence experts did not believe claims that Saddam Hussein had in the recent past sought to purchase uranium from Niger. Two sentences in the seven-sentence paragraph mention Wilson’s wife.

The memo was delivered to Secretary of State Colin L. Powell on July 7, 2003, as he headed to Africa for a trip with President Bush aboard Air Force One. Plame’s name was released publicly seven days later in a syndicated column by Robert D. Novak.

Wilson says his wife’s identity was revealed to retaliate against him for accusing the Bush administration of “twisting” intelligence to justify the Iraq war. On July 6, he cited a secret mission he conducted in February 2002 for the CIA, and where he determined there was no evidence that Iraq was seeking uranium for a nuclear weapons program in the African nation of Niger.

Presidential advisor Karl Rove and Vice President Dick Cheney’s Chief of Staff  discussed Wilson’s wife’s CIA connection with at least two reporters that she helped arrange his trip.

Karl Rove, however, told a grand jury investigating the leak he learned Plame’s name from Novak a few days before telling another reporter she worked at the CIA and played a role in her husband’s mission, according to a lawyer familiar with Rove’s account. Rove has also testified that the first time he saw the State Department memo was when “people in the special prosecutor’s office” showed it to him, says Robert Luskin, his attorney.

“He had not seen it or heard about it before that time,” Luskin said.

Other administration officials were on the trip to Africa included senior adviser Dan Bartlett and then-White House spokesman Ari Fleischer.

The Wall Street Journal also reported Tuesday that the memo made it clear that information about Wilson’s wife was sensitive and should not be shared.