Al Capone is convicted of income tax evasion.

Al Capone, one of the most infamous gangsters in American history, was convicted of income tax evasion on October 17, 1931. Despite his involvement in countless illegal activities—such as bootlegging, gambling, and organized crime—law enforcement struggled for years to find solid evidence linking him directly to these crimes. However, federal investigators eventually discovered that Capone had failed to pay taxes on his vast illicit income, a technical but powerful charge that would finally bring him down. This shift in strategy, led by the U.S. Treasury Department and investigator Eliot Ness, marked a turning point in how authorities pursued organized crime figures.

During the trial, prosecutors presented meticulous financial records showing Capone’s lavish spending despite having no legitimate source of income. His defense team attempted to argue that he had not intentionally evaded taxes, but the evidence—backed by ledgers, witnesses, and accountants—proved overwhelming. The jury found Capone guilty on five counts of tax evasion, and the judge sentenced him to 11 years in federal prison, the harshest penalty ever imposed for tax-related offenses at the time. He was also fined $50,000 and charged with court costs, effectively ending his criminal reign in Chicago.

Capone began serving his sentence at the Atlanta U.S. Penitentiary, but due to his continued influence and special treatment, he was later transferred to Alcatraz in 1934. The isolation and harsh conditions took a toll on his health, especially as he suffered from neurosyphilis, which progressively deteriorated his mental state. By the time of his release in 1939, Al Capone was a shadow of his former self, both physically and mentally. His conviction for income tax evasion not only symbolized the fall of one of America’s most notorious criminals but also demonstrated how the U.S. government could use financial laws to combat organized crime when traditional methods failed.