"Machine Gun" Jack McGurn (1905 - February 15, 1936) was a member of Alphonse Capone's Chicago based mafia organization and believed to be the principal assassin and planner of the St. Valentine's Day Massacre. He was born James DeMora in a Chicago suburb before taking up a career in boxing as a teenager and changing his name to 'Battling' Jack McGurn. Sometime in the 1920's, McGurn joined Capone's gang, allegedly to avenge the murder of his father by the Genna crime family. Through his career as Capone's principal hitman and bodyguard, McGurn is credited with over two dozen murders of rival gang members. The most infamous of these was the attempted killing of Bugs Moran on St. Valentine's Day (St. Valentine's Day Massacre) in 1929. McGurn himself was murdered, in a Chicago bowling alley, on St. Valentine's Day in 1936, apparently the victim of a mob hit.