Al Capone marked Capone's rule. Organized crime in the city had a lower profile once Prohibition was repealed, already wary of attention after seeing Capone's notoriety bring him down, to the extent that there is a lack of consensus among writers about who was actually in control and who was a figurehead "front boss". Prostitution, labor union racketeering, and gambling became moneymakers for organized crime in the city without incurring serious investigation. In the late 1950s, FBI agents discovered an organization led by Capone's former lieutenants reigning supreme over the Chicago underworld. After Capone was released from prison, he was referred to
Al Capone suspected of being involved. Torrio headed an essentially Italian organized crime group that was the biggest in the city, with Capone as his right-hand man. He was wary of being drawn into gang wars and tried to negotiate agreements over territory between rival crime groups. The smaller North Side Gang led by Dean O'Banion (also known as Dion O'Banion) was of mixed ethnicity, and it came under pressure from the Genna brothers who were allied with Torrio. O'Banion found that Torrio was unhelpful with the encroachment of the Gennas into the North Side, despite his pretensions to be a settler