The release in April of once-classified details about harsh Bush-era interrogation techniques has caused a squall of recriminations among congressional and Bush administration leaders who knew about the program.
Pelosi waded into that debate when she told reporters last month that she had been briefed on the authorized techniques in 2002, before she was elected Minority Leader by House Democrats, but was not told that waterboarding had already been used on a prisoner.
At the time Pelosi was a member of the House Permanent Select Committee on Intelligence.
Waterboarding, which simulates drowning, is the most severe of the 10 techniques approved by the Bush White House.
There is no record that Pelosi objected to using the techniques.
The CIA on Wednesday sent the House and Senate intelligence committees a chart describing the 40 congressional briefings at which the interrogation program was discussed, describing who was briefed, on what date, and on what subjects. Pelosi is only mentioned in the first briefing, held on Sept. 4, 2002.
The chart, drawn from the CIA briefers' memories and meeting notes, said the meeting described the interrogation techniques that had been used on alleged terrorist Abu Zubaydah. But the CIA chart does not specifically mention the use of waterboarding at that briefing.
According to legal memos released in April, Abu Zubayda was the first of three prisoners to be waterboarded. He underwent the procedure at least 83 times in August 2002.
The first mention of waterboarding comes in the description of a February 2003 meeting attended by Pelosi's successor on the House Intelligence Committee, California Democrat Jane Harman. Harman wrote to the CIA expressing concern about the techniques, the only known objection formally raised by a member of Congress at that time.
According to the charts, the CIA specifically discussed waterboarding in 13 of the 40 congressional briefings.
Pelosi spokesman Brendan Daly said Pelosi stands by her recollection of the meeting.
"As this document shows, the speaker was briefed only once, in September 2002," said Daly. "The briefers described these techniques, said they were legal, but said that waterboarding had not yet been used."
Even the CIA suggests that its account of the meetings will not settle the debate over who knew what and when.
"In the end, you and the Committee will have to determine whether this information is an accurate summary of what actually happened," states the May 6 cover letter from CIA Director Leon Panetta to Rep. Silvestre Reyes, Democratic chairman of the House Intelligence Committee.
Rep. Pete Hoekstra, the top Republican on that committee, said Thursday that calls for truth commissions or prosecutions for those who approved or carried out harsh interrogations ignore that Congress was fully informed about the methods.
"I think that nobody wants to take any accountability for it," Hoekstra said. "Is it fair to go after people in the CIA or at the Justice Department when Congress was briefed on this program and knew it was going on? That doesn't seem very fair to me. If there is going to be any accountability, (Congress) is where it needs to start."
Pelosi was elected House Minority Leader in November 2002, and became House Speaker after the Democrats regained a majority in the chamber in 2006.