Turning informant after his brother Larry became an FBI informant and gave up their rackets, Fiato put away many major mob gangsters in both Los Angeles and Boston. After joining the witness protection program, Fiato became a tabloid celebrity thanks to his testimony at the O. J. Simpson murder case, his appearance on the Howard Stern Show, and his relationship with Denise Brown, the sister of Simpson's murdered ex-wife. Fiato also cooperated with journalist John L. Smith, who wrote his biography "The Animal Hollywood: Anthony Fiato's Life in the Mafia".