The Federal Bureau's investigation of Al Capone arose from his reluctance to appear before a Federal Grand Jury on March 12, 1929, in response to a subpoena. On March 11, his lawyers formally filed for postponement of his appearance, submitting a physician's affidavit dated March 5, which attested that Capone, in Miami, had been suffering from bronchial pneumonia, had been confined to bed from January 13 to February 23, and that it would be dangerous to Capone's health to travel to Chicago. His appearance date before the grand jury was re-set for March 20.
On request of the U.S. Attorney's Office, Bureau of Investigation Agents obtained statements to the effect that Capone had attended race tracks in the Miami area, that he had made a plane trip to Bimini and a cruise to Nassau, and that he had been interviewed at the office of the Dade County Solicitor, and that he had appeared in good health on each of those occasions.
Capone appeared before the Federal Grand Jury at Chicago on March 20, 1929, and completed his testimony on March 27. As he left the courtroom, he was arrested by Agents for Contempt of Court, an offense for which the penalty could be one year and a $1,000 fine. He posted $5,000 bond and was released.