William Mark Felt was the individual that turned out to be the famous Deep Throat informant during the Watergate scandal.
William Mark Felt Sr. worked for the Federal Bureau of Investigation (FBI) from May 1942 until he retired in June 1973.
While he served as Associate Director, Felt performed as an anonymous informant, nicknamed "Deep Throat."
Deep Throat is the pseudonym given to the secret informant who provided information in 1972 to Bob Woodward, who shared it with Carl Bernstein.