The St. Valentine's Day Massacre (1967)

Storyline:
Chicago February 14th 1929. Al Capone finally establishes himself as the city's boss of organised crime. In a north-side garage his hoods, dressed as policemen, surprise and mow down with machine-guns the key members of Bugs Moran's rival gang. The film traces the history of the incident, and the lives affected and in some cases ended by it.