W. Mark Felt and daughter Joan Felt in front of their home in California (2005 file photo)

W. Mark Felt, the confidential source who helped unravel the Watergate scandal that led to President Richard Nixon's resignation, has died at the age of 95.

Felt died Thursday in Santa Rosa, California, where he lived for many years.

Felt was the second-ranking official at the FBI when a group of burglars broke into the headquarters of the Democratic National Committee at Washington's Watergate Hotel in June 1973. Under the nickname "Deep Throat," he secretly supplied information about the break-in - and the White House's efforts to hinder the FBI's investigation - to Washington Post reporters Bob Woodward and Carl Bernstein.  

The journalists often quoted "Deep Throat" in news reports which
showed Nixon administration officials had paid the burglars.  Mr. Nixon later resigned during his impeachment trial in 1974.

Woodward and Bernstein tightly guarded "Deep Throat's" identity for decades, until Felt himself came forward in 2005.

Felt retired from the FBI in 1973 after 31 years with the agency.  He was tried and convicted in 1980 for authorizing illegal break-ins at the homes of members of the radical left-wing group Weather Underground.  Mr. Nixon himself testified on Felt's behalf, despite the ex-president's earlier suspicions that Felt was leaking Watergate secrets.

President Ronald Reagan pardoned Felt in 1981.  

Some information for this report was provided by Bloomberg and AP.