The massacre had immediate and lasting impacts on American law and society:
Led by the infamous Alphonse "Al" Capone , who sought total control over Chicago's illegal bootlegging operations.
Six died instantly, while the seventh, Frank Gusenberg, lived for a short time but refused to break the "code of silence" before he died.
Four to six assailants entered the garage. At least two were disguised in police uniforms, leading the victims to believe it was a routine raid.
The seven men were ordered to line up against a brick wall. The attackers then opened fire with Thompson submachine guns and shotguns, firing over 70 rounds.