His investigation of Communist Party infiltration of the National Maritime Union led Representative Louis B. Heller to introduce legislation in 1951 to investigate the charges. In 1951 and 1952, Riesel provided Senator Pat McCarran with information that led to a Senate investigation into communist influence in the United Public Workers of America. In 1952, he publicly alleged before the Subcommittee on Internal Security (led at the time by Sen. McCarran) that Local 65 of the Distributive, Processing and Office Workers of America was controlled by the Communist Party. The same year, he denounced Gambino crime family member Anthony "Tough Tony" Anastasio for engaging in labor racketeering. Anastasio sued Riesel for $1 million for libel, but the suit was thrown out of court.