Mark Felt, the FBI official who as the anonymous journalistic source “Deep Throat” helped bring down President Richard Nixon, died on Thursday at his home in Santa Rosa, Calif. He was 95.

Felt suffered from congestive heart failure but the immediate cause of death was not known on Thursday night.

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

Jones said the family would issue a formal statement today.

In 2005, more than 30 years after his whistle-blowing helped topple a presidency, Felt held a press conference on the front steps of his Santa Rosa home.

Felt, then 91, revealed that he was “Deep Throat,” the anonymous source who in 1972 leaked information to the Washington Post reporters Bob Woodward and Carl Bernstein about the Watergate scandal that eventually led to Nixon’s resignation in 1974.

Felt’s role, but not his identity, was 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.

Felt’s role is explored in detail in Woodward’s 2005 book, “The Secret Man,” and in Felt’s 2006 autobiography, “A G-Man’s Life.”

Felt, who lived in Alexandria, Va, after his 1973 resignation from the FBI, moved to Santa Rosa in 1991, and lived there with his daughter, Joan Felt, until his death.

Felt was born in Twin Falls, Idaho, on Aug. 17, 1913, the son of carpenter and building contractor Mark Earl Felt and his wife, the former Rose Dygert. He graduated from Twin Falls High School in 1931 and received his B.A. from the University of Idaho in 1935.

After graduation, Felt moved to Washington, D.C., and got his first taste of political life working in the office of Sen. James Pope, D-Idaho. In 1938, he married Audrey Robinson, a fellow Idahoan who also had moved to Washington and whom he had known since they were both students at the University of Idaho.

In an early indication of both his ambition and propensity for hard work, Felt worked during the day and attended George Washington University Law School at night. He earned his law degree in 1940, and was admitted to the bar in the District of Columbia bar in 1941.

After graduation, Felt took a position at the Federal Trade Commission, but left after only a few months in search of a more adventurous career.

At the FBI

In his memoir, “The FBI Pyramid,” published in 1979, Felt said the FTC had asked him to investigate whether a toilet paper brand called “Red Cross” gave consumers the mistaken impression it was endorsed by the American Red Cross.

World War II was in full swing in January 1942 when Felt went to work for the FBI. He was immediately assigned to the Espionage Section, tracking down Nazi spies operating in the U.S. His investigations led to the arrest of two top-level spies and brought him to the attention of top FBI officials.

According to the Washington Post, it was during this period that Felt learned counter-intelligence tricks that became part of his relationship with the Post reporters: A flowerpot on Woodward’s balcony would indicate that the reporter required a meeting, while a clock face inked on the reporter’s daily New York Times would reveal the time Felt would be waiting in an underground parking garage.

When the war ended in 1945, the Espionage Section was abolished, and Felt was assigned to the Seattle field office where he remained for nine years.

Felt grew restless, and in 1954 met with FBI Director J. Edgar Hoover and talked of his ambitions. Felt’s succinct, no-nonsense style appealed to Hoover, and Felt was quickly moved through five field offices and given promotions at each move.

In 1956, as special agent in charge in Salt Lake City Felt became part of the FBI push against the Mafia, gathering information through informants and wiretaps about the underworld owners of gambling casinos in Las Vegas and Reno.

He was brought back to Washington in 1962 to be Hoover’s ally in the FBI’s struggle to preserve its independence from a succession of presidents who distrusted Hoover and sought to replace him.

With Hoover’s death in 1972, Felt became associate director, second in command of the massive federal agency and reporting directly to Acting Director Patrick Gray.

Watergate

As associate director, Felt was one of the first to learn about the 1972 burglary at the Democratic National Committee headquarters in the Watergate apartment complex and to realize its connection to Nixon’s re-election campaign.

Days after the break-in, Nixon and White House staff talked about putting pressure on the FBI to slow down the investigation. Fearing that the investigation would be sabotaged and justice subverted, Felt began giving information to Woodward, whom he had known for several years.

Although his name was frequently raised as the suspected source, Felt denied for more than 30 years that he was the person who met Woodward and Bernstein in underground parking garages to provide clues to Watergate. His own family learned of his role only in 2002.

Felt resigned from the FBI in 1973. In 1976, he was indicted with another FBI official, Edward Miller, for authorizing illegal searches of the homes of relatives and friends of Weather Underground members.

The group, part of a radical antiwar movement, had planted bombs at the Capitol, the Pentagon and the State Department in the early 1970s.

Felt took responsibility for ordering the break-ins, saying he knew they were outside the law, but felt the actions were in the best interest of the country.

“To not take action against these people and know of a bombing in advance would simply be to stick your fingers in your ears and protect your eardrums when the explosion went off and then start the investigation,” Felt told CBS television during that period.

Felt and Miller were convicted and fined in 1980, but were pardoned a few months later by President Ronald Reagan. Reagan said the men had “acted on high principle to bring an end to the terrorism that was threatening our nation.”

Felt’s wife, Audrey Felt, died in 1984. He is survived by two children, Joan Felt and Mark Felt Jr., and four grandchildren: Nick Jones, of Los Angeles, Rob Jones, of Cotati, William Felt, of San Francisco and Mark Felt.