Watergate source Deep Throat dies at 95

The "most famous anonymous source in American history" died in his sleep Thursday at a California hospice, reported Bob Woodward, one of the two Post journalists who exposed the Watergate affair.

Felt was associate director of the Federal Bureau of Investigation (FBI) when he began helping the reporters. After revealing his identity in 2005, he said he never considered himself a hero, but was just "trying to help".

His daughter Joan Felt said Felt had big breakfast before saying he was tired, and went to sleep, the Post reported. "He slipped away," she said.

Felt was in poor health when he revealed he was the shadowy informant of late-night meetings in dark garages made famous in the book and movie "All the Presidents Men".

He kept his role secret for 33 years, not even telling his family.

It was with Felt's crucial input that Woodward and Carl Bernstein could write a series of investigative scoops about the Nixon administration’s involvement in the June 1972 burglary of the Democratic National Committee headquarters at the Watergate complex in the U.S. capital.

The scandal -- including the White House's attempts at cover-up -- ultimately led to Nixon becoming the first U.S. president to resign in disgrace in August 1974.

THE MAN WHO KNOWS EVERYTHING
Felt was born in Twin Falls, Idaho, and worked for an Idaho senator during graduate school. After law school at George Washington University he spent a year at the Federal Trade Commission. Felt joined the FBI in 1942 and worked as a Nazi hunter during World War Two.

Ironically, while providing crucial information to the Post, Felt also was assigned to ferret out the newspapers source. The investigation never went anywhere, but plenty of people, including those in the White House at the time, guessed that Felt, who was leading the investigation into Watergate, may have been acting as a double agent.

The Watergate tapes captured White House chief of staff H.R. Haldeman telling Nixon that Felt was the source, but they were afraid to stop him.

Nixon asks: "Somebody in the FBI?"

Haldeman: "Yes, sir. Mark Felt ... If we move on him, he’ll go out and unload everything. He knows everything that’s to be known in the FBI."

Felt left the FBI in 1973 for the lecture circuit. Five years later he was indicted on charges of authorizing FBI break-ins at homes associated with suspected bombers from the 1960s radical group the Weather Underground. President Ronald Reagan pardoned Felt in 1981 while the case was on appeal - a move applauded by Nixon.

Woodward and Bernstein said they would not reveal the sources identity until he or she died, and finally confirmed Felt's role only after he came forward.

O’Connor said Thursday that his friend appeared to be at peace since the revelation.

"What I saw was a person that went from a divided personality that carried around this heavy secret to a completely integrated and glowing personality over these past few years once he let the secret out," he said.

Felt is survived by two children, Joan Felt and Mark Felt Jr., and four grandchildren. His wife, Audrey Felt, died in 1984.