George "Bugs" Moran inherited the North Side gang in Chicago from Mob boss Dion O'Bannion, and by became locked in a bloody turf war with Al Capone. The violence between the two bosses climaxed in 1929 with the St. Valentine's Day Massacre.
The Saint Valentine's Day Massacre is the name given to the 1929 murder of seven mob associates as part of a Prohibition-era conflict between two powerful criminal gangs in Chicago: the South Side Italian gang led by Al Capone and the North Side Irish gang led by Bugs Moran.
In severe decline from syphilis he had contracted when he was a much younger man, by 1946, he was reduced to the mentality of a 12-year-old child, according to his doctor, and would rant about Bugs Moran, Communists and immigrants. He had a stroke on January 21, 1947, and died from cardiac arrest four days later.