Al Capone Mabel Walker Willebrandt recognized that mob figures publicly led lavish lifestyles yet never filed tax returns, and thus could be convicted of tax evasion without requiring hard evidence to get testimony about their other crimes. She tested this approach by prosecuting a South Carolina bootlegger. In 1927, the Supreme Court ruled in "United States v. Sullivan" that illegally earned income was subject to income tax; Justice Oliver Wendell Holmes Jr. rejected the argument that the Fifth Amendment protected criminals from reporting illegal income. The IRS special investigation unit chose Frank J. Wilson to investigate Capone, with the focus on his
Al Capone completed his term in Alcatraz on January 6, 1939, and was transferred to the Federal Correctional Institution at Terminal Island in California to serve out his sentence for contempt of court. He was paroled on November 16, 1939. The main effect of Capone's conviction was that he ceased to be boss immediately on his imprisonment, but those involved in the jailing of Capone portrayed it as considerably undermining the city's organized crime syndicate. Far from being smashed, the Chicago Outfit continued without being troubled by the Chicago police, but at a lower level and without the open violence that had