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 signaled for accomplices armed with machine guns and shotguns. Photos of the slain victims shocked the public and damaged Capone's reputation. Within days, Capone received a summons to testify before a Chicago grand jury on charges of federal Prohibition violations, but he claimed to be too unwell to attend. Capone was primarily known for ordering other men to do his dirty work for him. One story, however, has Capone, having discovered that three of his men—Scalise, Anselmi, and Giunta—were conspiring against him with a rival gangster, Joe Aiello, reportedly arranging for the conspirators to dine with him and his bodyguards.