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 and threatened to arrest his family. He was charged with perjury for making these statements, but was acquitted after a three-day trial in July. In September, a Chicago judge issued a warrant for Capone's arrest on charges of vagrancy, and then used the publicity to run against Thompson in the Republican primary. In February 1931, Capone was tried on the contempt of court charge. In court, Judge James Herbert Wilkerson intervened to reinforce questioning of Capone's doctor by the prosecutor. Wilkerson sentenced Capone to six months, but he remained free while on appeal of the contempt conviction. Assistant Attorney General