The second in 1964, known as the Valachi hearings, investigated the operations of organized crime and featured the testimony of Joseph Valachi, the first American mafia figure to testify about the activities of organized crime. He continued his efforts against organized crime, supplying the political influence for the anti-organized crime law Racketeer Influenced and Corrupt Organizations Act (RICO) until 1973 when he switched to investigating political subversion. During this period, he hired Robert F. Kennedy as chief counsel and vaulted him into the national spotlight. He investigated numerous cases of government corruption including numerous defense contractors and Texas financier Billie Sol Estes.