The spark of the Omaha Race Riot of 1919 occurred when a black man named Will Brown was arrested and accused of raping a young white woman from South Omaha. A mob of mostly white ethnic young men marched from South Omaha (rallied and led by a henchman of Dennison's) and converged on the Douglas County Courthouse, where the jail was. In the evening the crowd grew larger and set the courthouse on fire, forcing police to turn Brown over to them. They lynched him, hanging him from a lamppost on the south side of the courthouse, then dragging his body through the streets and burning it. The mob was mostly European-born immigrants and ethnic European Americans. The mayor attempted to intervene and was also hanged; he was saved only by a last-minute rescue by federal agents. The city had to ask for help from Federal troops to quell the disorder, and their arrival was delayed because of a series of communication problems. The commander stationed troops in South Omaha to prevent more mobs from forming, and in North Omaha to protect the blacks.