Although he was never successfully convicted of racketeering charges, Capone's mobster career ended in 1931, when he was indicted and convicted by the federal government for income-tax evasion. He was sent to a series of prisons including Alcatraz, which was the longest and most famous of his sentences.
Weapons: Guns, brass knuckles
Reign: 1920's and '30s
Key Battles: The St. Valentine's Day Massacre eliminated some of Capone's enemies, but outraged the general public.