On the freezing morning of February 14, 1929, George Bugs Moran was running late to a garage on North Clark Street, where a truckload of hijacked Canadian whiskey was waiting. He saw a police car out front, assumed a raid, and ducked into a cafe. Inside the SMC Cartage Company garage, men in police uniforms lined seven people against a wall and opened fire. A lookout had mistaken Albert Weinshank for Moran. The boss of the North Side Gang lived, but his top enforcers were gone, and with them his power to hold territory against Al Capone.

This episode traces the man behind the name. He was born Adelard Leo Cunin in St. Paul, Minnesota, in August 1893, attended a private Catholic school, and had three jail stints before he turned 21. In Chicago he gave police the alias George Moran, and the underworld added Bugs for his violent instability. Prohibition made that reputation an asset. He was a proud Catholic who refused to touch prostitution and despised Capone for it, yet he helped pour more than a thousand rounds into Capone’s headquarters.

• Moran rose through the North Side Gang of Dean O’Banion and Hymie Weiss, and became its boss after both were murdered.
• When St. Paul mob boss Danny Hogan died in a 1928 car bombing, Moran went home and stood guard outside the family’s house.
• Frank Gusenberg, dying of his wounds, told police that nobody shot him. Moran broke the same code by publicly accusing Capone.
• Capone was at his Florida estate that morning, and no one was ever convicted for the massacre.
• After repeal Moran slid into forged checks, a tavern robbery in Dayton, and a bank job. He died of lung cancer at Leavenworth on February 25, 1957, aged 63.