 During a grand jury investigation in 1976, Felt was called to testify.The prosecutor, J. Stanley Pottinger, Assistant Attorney General for Civil Rights, discovered that Felt was "Deep Throat", but the secrecy of the proceedings protected the information from being public.In 1992 James Mann, who had been a reporter at "The Washington Post" in 1972 and worked with Woodward, wrote a piece for "The Atlantic Monthly", saying the source had to have been within the FBI.