HBO’s hit series Boardwalk Empire, about the Prohibition-era gangsters that enriched themselves by smuggling liquor in defiance of U.S. law did their homework. All the historical figures that featured prominently in the Chicago and New York operations feature prominently on the show. Johnny Torrio, the Chicago gang leader was there, and under him a young buck named Al Capone. The actual Al Capone rose to become Torrio’s right hand-man, and then took over the empire, ruling Chicago as his own personal fiefdom. While his men were making “hits” on rival mob families, Capone remained tantalizingly out of judicial reach. At least as far as the shootings were concerned — but the FBI found his weakness.

On this day, October 17, in 1931, Al Capone was convicted on tax evasion charges. He was sentenced to 11 years, ordered to pay all back taxes, with interest, plus a fine.

At the height of his career, Capone was said to have remarked he could not be taken in for tax evasion, because his profits from the liquor trade were off the books. Had he followed the news of those years he might have seen the courts decide differently. In what became a dress rehearsal for the Al Capone case, the Supreme Court ruled in the trial of a small-time alcohol distributor that just because the profits are illicit doesn’t mean they aren’t subject to taxes.