Sam 'Momo' Giancana rose to power during the Capone years in Prohibition-era Chicago. By 1957, J. Edgar Hoover denied an 'Underworld' until fifty mobsters were caught at a summit. Giancana's high-profile relationships with Phyllis McGuire and Frank Sinatra kept him in the spotlight. Ultimately, he was shot point-blank in his home, likely by jealous mobsters.