Aladena "Jimmy the Weasel" Fratianno (November 14, 1913 - June 30, 1993) was an Italian-born American mobster based in Cleveland, Ohio, and later acting head of the Los Angeles crime family before becoming a US government witness. Fratianno was the most powerful mobster to become a federal witness until Sammy "the Bull" Gravano agreed to testify against the Gambino crime family in 1991.