 Many of the events in the film are based upon the life of Al Capone  and the Chicago gang wars of the 1920s. In order, the most prominent  are: 1. When Tony kills his boss, "Big Louie" Costillo in the lobby  of his club is based on when Capone killed his first boss, "Big Jim"  Colosimo. 2. Guino (George Raft) comes into Tonys apartment wearing  a flower in his coat lapel and we learn he killed rival boss,  OHara. In real life, Capones men killed Dion OBannon in his  flower shop. 3. When Gaffney (Boris Karloff) leads a caravan of cars  in a drive