His reputation as a ruthless rival in Chicago was solidified after the St. Valentine's Day Massacre on February 14, 1929, when seven members of the "Bugs" Moran mob were machine-gunned against a garage wall by rivals posing as police.
Capone's rule over Chicago was stopped in 1931 when he was sent to prison for tax evasion. After his release he was hospitalized for dementia as a result of having advanced syphilis. His years as a mobster were over. Capone died in his house in Florida, never returning to Chicago after his release from prison.
See Also: Glossary of Common Mafia Terms