WASHINGTON – Breaking a silence of 30 years, former FBI official W. Mark Felt stepped forward Tuesday as Deep Throat, the secret Washington Post source that helped bring down President Nixon during the Watergate scandal.

Within hours, the paper confirmed his claim.

“It’s the last secret” of the story, said Ben Bradlee, the paper’s top editor at the time the riveting political drama played out three decades ago.

It tumbled out in stages during the day – first when a lawyer quoted Felt in a magazine article as having said he was the source; then when the former FBI man’s family issued a statement hailing him as a “great American hero.” Finally the Post’s confirmation resolved one of the most enduring mysteries in American politics and journalism.

The scandal that brought Nixon’s resignation began with a burglary and attempted tapping of phones in Democratic offices at the Watergate office building during his 1972 re-election campaign. It went on to include disclosures of covert Nixon administration spying on and retaliating against a host of perceived enemies. But the most devastating disclosure was Nixon’s own role in trying to cover up his administration’s involvement.

“I’m the guy they used to call Deep Throat,” Felt, the former No. 2 man at the FBI, was quoted as saying in Vanity Fair.

John Dean, counsel in Nixon’s White House and the government’s leading informant in the Watergate investigation, said Felt’s admission raises more questions than it answers. Among them, how Felt gained access to the information he gave the Post, said Dean, who served four months in prison for his role in the scandal.

“How in the world could Felt have done it alone?” Dean asked in an interview with The Associated Press on Tuesday. He said he couldn’t see how Felt, then in charge of the FBI’s day-to-day operations, could have had time to meet reporters in parking garages at night and leave secret messages to arrange meetings.

Felt kept his secret even from his family for almost three decades before his declaration.

Felt, now 91, lives in Santa Rosa, Calif., and is said to be in poor mental and physical health because of a stroke. His family did not immediately make him available for comment, asking the news media to respect his privacy “in view of his age and health.”

A grandson, Nick Jones, read a statement. “The family believes that my grandfather, Mark Felt Sr., is a great American hero who went well above and beyond the call of duty at much risk to himself to save his country from a horrible injustice,” it said. “We all sincerely hope the country will see him this way as well.”

In a statement issued later, Watergate reporters Bob Woodward and Carl Bernstein said, “W. Mark Felt was ‘Deep Throat’ and helped us immeasurably in our Watergate coverage. However, as the record shows, many other sources and officials assisted us and other reporters for the hundreds of stories that were written in The Washington Post about Watergate.”

Among other things, Deep Throat urged the reporters to follow the money trail – from the financing of burglars who broke into the Democratic National Committee offices to the financing of Nixon’s re-election campaign.

The reporters and Bradlee had kept the identity of Deep Throat secret at his request, saying his name would be revealed upon his death. But then Felt revealed it himself.

Even the existence of Deep Throat, nicknamed for an X-rated movie of the early 1970s, was kept secret for a time. Woodward and Bernstein revealed their reporting had been aided by a Nixon administration source in their best-selling book “All the President’s Men.”

A hit movie starring Robert Redford as Woodward, Dustin Hoffman as Bernstein and Hal Holbrook as Deep Throat was made in 1976. In the film, Holbrook’s shadowy, cigarette-smoking character met Redford in dark parking garages and provided clues about the scandal.

The movie portrayed cloak-and-dagger methods employed by Woodward and Deep Throat. When Woodward wanted a meeting, he would position an empty flowerpot containing a red flag on his apartment balcony. When Deep Throat wanted to meet, the hands of a clock would appear written inside Woodward’s New York Times.

The identity of the source has sparked endless speculation over the last three decades. Nixon chief of staff Alexander Haig, White House press aide Diane Sawyer, White House counsel John Dean and speechwriter Pat Buchanan and adviser Len Garment were among those mentioned as possibilities.

Felt himself was mentioned several times over the years as a candidate for Deep Throat, but he regularly denied he was the source.

“I would have done better,” Felt told The Hartford Courant in 1999. “I would have been more effective. Deep Throat didn’t exactly bring the White House crashing down, did he?”

Felt had hoped to succeed mentor J. Edgar Hoover as FBI director after Hoover’s death, but was passed over by Nixon for the job.

Nixon chief counsel Charles “Chuck” Colson worked closely with Felt in the Nixon administration and expressed surprise at the disclosure.

“Mark first served this country with honor, and I can’t imagine how Mark Felt was sneaking in dark alleys leaving messages under flowerpots and violating his oath to keep this nation’s secrets. I cannot compute that with the Mark Felt that I know,” Colson said in an interview Tuesday with The Associated Press. Colson pleaded no contest to an obstruction of justice charge in the Watergate scandal and served time in prison.

Another Nixon associate who wound up behind bars, G. Gordon Liddy, said he didn’t consider Felt a hero for going to the Post reporters.

“If he were interested in performing his duty, he would have gone to the grand jury with his information,” Liddy, who was finance counsel at Nixon’s re-election committee and helped direct the break-in, said in an interview on CNN.

The FBI declined to comment Tuesday on Felt’s admission.

Felt had expressed reservations in the past about revealing his identity, and about whether his actions were appropriate for an FBI man, his grandson said.

According to the article, Felt once told his son, Mark Jr., that he did not believe being Deep Throat “was anything to be proud of. … You [should] not leak information to anyone.”

His family members thought otherwise, and persuaded him to talk about his role in the Watergate scandal, saying he deserves to receive accolades before his death. His daughter, Joan, argued that he could “make enough money to pay some bills, like the debt I’ve run up for the children’s education.”

“As he recently told my mother, ‘I guess people used to think Deep Throat was a criminal, but now they think he’s a hero,'” Jones said.

Woodward, who had visited with Felt as recently as 1999, refused to confirm or deny, even to the man’s family, that Felt was his source, and wondered whether Felt was mentally competent to decide whether to go public after all these years, the magazine reported.

Woodward and Bernstein were the first reporters to link the Nixon White House and the break-in at the Democratic National Headquarters.

Nixon, facing almost-certain impeachment for helping to cover up the break-in, resigned in August 1974. Forty government officials and members of Nixon’s re-election committee were convicted on felony charges.

Felt was convicted in the 1970s for authorizing illegal break-ins at homes of people associated with the radical Weather Underground. He was pardoned by President Reagan in 1981.

Associated Press Writers Larry McShane in New York and Greg Sandoval in Santa Rosa, Calif., contributed to this report.