Provoked by police brutality, on August 23, 1917, members of the all-black 24th Infantry rioted in Houston, Texas. Sixteen white civilians and four black soldiers were killed. One hundred and eighteen men were court-martialed, and after the trials, nineteen were hanged and eighty-one jailed in Leavenworth, Kansas. The NAACP began a long campaign to win clemency for the imprisoned soldiers. On February 7, 1924, a NAACP delegation led by James Weldon Johnson presented to President Calvin Coolidge a petition of 125,000 signatures asking pardon for the fifty-four men still in prison. As a result, all of the sentences were reduced and twenty men were freed. President Franklin Roosevelt ordered the release of the last prisoners in 1938.