In San Francisco, a bomb at a Preparedness Day parade on Market Street kills 10 people and wounds 40. The bomb was hidden in a suitcase. The parade was organized by the city's Chamber of Commerce in support of America's possible entrance into World War I. San Francisco was suffering through severe labor strife at the time, and many suspected that anti-war labor radicals were responsible for the terrorist attack.
Labor leader Tom Mooney, his wife Rena, his assistant Warren K. Billings, and two others were soon charged by District Attorney Charles Fickert with the bombing. The case attracted international interest because all evidence, with the exception of a handful of questionable witness accounts, seemed to point unquestionably to their innocence. Even after confessions of perjured testimony were made in the courtroom, the trial continued, and in 1917 Mooney and Billings were convicted of first-degree murder, with Billings sentenced to life imprisonment and Mooney sentenced to hang. The other three defendants were acquitted. Responding to international outrage at the conviction, President Woodrow Wilson set up a "mediation commission" to investigate the case, and no clear evidence of their guilt was found. In 1918, Mooney's sentence was commuted to life imprisonment.
During the next two decades, many groups and individuals petitioned California to grant the two men a new trial. By 1939, when evidence of perjury and false testimony at the trial had become overwhelming, newly elected Governor Culbert Olson pardoned Mooney and commuted Billing's sentence to time served. Billings was not officially pardoned until 1961.