In 1998, when President Bill Clinton ordered military strikes against a suspected chemical weapons factory in Sudan, Mary O. McCarthy, a senior intelligence officer assigned to the White House, warned the president that the plan relied on inconclusive intelligence, two former government officials said.
McCarthy's reservations did not stop the attack on the factory, which was carried out in retaliation for al-Qaida's bombing of two American embassies in East Africa. But they illustrated her willingness to challenge intelligence data and methods endorsed by her bosses at the Central Intelligence Agency.
On Thursday, the CIA fired McCarthy, 61, accusing her of leaking information to reporters about overseas prisons operated by the agency in the years since the Sept. 11 attacks. But despite McCarthy's independent streak, some colleagues who worked with her at the White House and other offices during her intelligence career say they cannot imagine McCarthy as a leaker of classified information.
As a senior National Security Council aide for intelligence from 1996 to 2001, she was responsible for guarding some of the nation's most sensitive secrets.
"We're talking about a person with great integrity who played by the book and, as far as I know, never deviated from the rules," said Steven Simon, a National Security Council aide in the Clinton administration who worked closely with McCarthy.
If in fact McCarthy was the leaker, Richard J. Kerr, a former CIA deputy director, said, "I have no idea what her motive was, but there is a lot of dissension within the agency and it seems to be a rather unhappy place." Kerr called McCarthy "quite a good, substantive person on the issues I dealt with her on."
In the case of the Al Shifa pharmaceutical plant in Khartoum, Sudan, her concerns may have been well-founded. Sudanese officials and the plant's owner denied any connection to al-Qaida.
After an article last November in the Washington Post reported that the CIA was sending terror suspects to clandestine detention centers in several countries, including some in Eastern Europe, Porter Goss, the agency's director, ordered polygraphs for intelligence officers who knew about certain "compartmented" programs, including the secret detention centers for terror suspects.
Government officials said that after McCarthy's polygraph examination showed the possibility of deception, the examiner confronted her and she disclosed having had conversations with reporters.
But some former CIA employees who know McCarthy remain unconvinced, arguing that the pressure from Goss and others in the Bush administration to plug leaks may have led the agency to focus on an employee on the verge of retirement, whose work at the White House during the Clinton administration had long raised suspicions within the current administration.
"It looks to me like Mary is being used as a sacrificial lamb," said Larry Johnson, a former CIA officer who worked for McCarthy in the agency's Latin America section.