On 13 March 1931, a federal grand jury met secretly on the government's claim that in 1924 Al Capone had a tax liability of $32,488.81. The jury returned an indictment against Capone that was kept secret until the investigation was complete for the years 1925 to 1929.
The grand jury later returned an indictment against Capone with twenty-two counts of tax evasion, totalling over $200,000. Capone and 68 members of his gang were charged with 5,000 separate violations of the Volstead Act. These income tax cases took precedence over the Prohibition violations.
Fearing that witnesses would be tampered with, and having doubts that the six-year statute of limitations would be upheld by the Supreme Court, a deal was secretly truck between Capone’s lawyers and government prosecutors. Capone was to plead guilty to a lighter charge and would receive between two and five years. However, when word got out, the press were outraged and campaigned against what they saw as a blatant whitewash.
The over-confident Capone, who believed he would receive less than five years in prison suddenly, became less cocky when he realised that his plea bargain was now null and void.
On 6 October 1931, fourteen detectives escorted Capone to the Federal Court Building. He was dressed in a conservative blue serge suit and without his usual pinkie ring and gaudy jewellery. It was inevitable that Capone’s henchmen procured a list of jury members to bribe, but unbeknown to Capone, the authorities had been aware of the plot.
When Judge Wilkinson entered the courtroom he suddenly demanded that the jury be exchanged with another in the same building. Capone and his lawyer were shocked. The fresh jury were even sequestered at night so that the Capone mob couldn't get to them.
During the trial Attorney George E. Q. Johnson made a mockery of Capone’s claim to be a ‘Robin Hood’ type figure and man of the people. He stressed the hypocrisy of man who would spend thousands of dollars on meals and luxuries but give little to the poor and unemployed. How he asked could Capone possess so much property, vehicles and even diamond belt buckles when his defence lawyers profess that their client had no income?
After nine hours of discussion on 17 October 1931, the jury found Capone guilty of several counts of tax evasion. Judge Wilkerson sentenced him to eleven years, $50,000 in fines and court costs of another $30,000. Bail was denied.
In August 1934, Capone was moved from a prison in Atlanta to the infamous Alcatraz in San Francisco. His days of privileges in prison were gone and contact with the outside world, even through letters and newspapers was minimal.
Capone’s health was exacerbated by tertiary syphilis and he became confused and disorientated. His sentence was finally reduced to six and a half years for good behaviour.
After release, Capone slowly deteriorated at his Palm Island palace. Mae, his wife stuck by him until 25 January 1947 when he died of cardiac arrest at age 48.