Mark Felt, the mysterious "Deep Throat" source who helped Washington Post reporters Bob Woodward and Carl Bernstein crack the Watergate scandal that brought down President Richard Nixon, has died at age 95.

Felt suffered from congestive heart failure but the exact cause of his death at home on Thursday was not immediately known, said the Press Democrat newspaper in Santa Rosa, California, 55 miles north of San Francisco.

In its report on Felt's death, the New York Times called him "the most famous anonymous source in American history."