Renown FBI agent Mark Felt, who became "the most famous anonymous source in American history" in the Watergate scandal which helped bring down disgraced U.S. President Richard Nixon, passed away.

Mark Felt is once again all over the news, only this time he's with his real name, and not the "Deep Throat" nickname he used back in the 1970s to leak information about President Richard Nixon and his aides to Washington Post reporters Bob Woodward and Carl Bernstein.

The former FBI agent died Thursday in Santa Rosa after suffering from congestive heart failure for several months, said family friend John D. O'Connor, who wrote the 2005 Vanity Fair article uncovering Felt's secret. The exact cause of death was not known right away.

"He was an important person for the history of our nation, but also such a gem and such a treasure to our family," his grandson, Nick Jones, said. "He was a great man."

Asked in one of his interviews how he would like to be remembered, Felt said he would want people to remember him as "a government employee who did his best to help everybody."

In 2005, more than 30 years since his collaboration with the Washington Post, Felt, who was 91 at the time, revealed one of the newspaper's best kept secrets telling reporters during a press conference on the front steps of his Santa Rosa home that he was the man behind "Deep Throat."

"I'm the guy they used to call Deep Throat," Felt told attorney John O'Connor.

While Felt's name was raised as a suspect on several occasions, including a James Mann article in a 1992 issue of Atlantic magazine where Mann explains why FBI had powerful incentives to undermine Nixon, Felt successfully managed to deflect attention usually by saying that if he had been Deep Throat he would have done a better job of exposing the wrongdoings at the White House.

A deputy associate director of the FBI, Felt was a controversial figure before disclosing his alter ego in 2005. He was convicted of authorizing illegal activities in pursuit of members of the radical Weather Underground and supported the bugging of Martin Luther King during the Kennedy administration, also opposing decisions to hire women as FBI agents.

The life and role of "Deep Throat" were depicted in a 1974 book titled "All the President's Men" by Woodward and Bernstein and in a film of the same title released in 1976. His role was explored in detail in Woodward's 2005 book, "The Secret Man," and in Felt's 2006 autobiography, "A G-Man's Life: The FBI," in which he said he saw himself as a "Lone Ranger" who could help derail a White House cover-up.

His confession in a 2005 Vanity Fair article prompted a never-ending debate whether he was a traitor, for betraying the commander in chief, or a hero, who should be lauded for sparing the country the strain of further high crimes and misdemeanors by the Nixon administration. But in his 2006 memoir, Felt said the ultimate purpose of telling the truth was accomplished.