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 after key witnesses recanted their statements. An indication of the attitude of local law enforcement to Capone's organization came in 1931 when Belcastro was wounded in a shooting; police suggested to skeptical journalists that Belcastro was an independent operator. The 1929 Saint Valentine's Day Massacre led to public disquiet about Thompson's alliance with Capone and was a factor in Anton J. Cermak winning the mayoral election on April 6, 1931. Capone was widely assumed to have been responsible for ordering the 1929 Saint Valentine's Day Massacre in an attempt to eliminate Bugs Moran, head of the North Side Gang. Moran