The spark for the riot occurred around midday. The two police officers broke up a craps game in the predominantly black neighborhood of San Felipe. When they chased after the men playing the game, one of the officers entered the house of Sara Travers. After talking to her briefly he hit her and dragged her out into the street and then proceeded to make an arrrest call on the nearby police phone. It was at this point a soldier from the battalion came to the scene and offered to take the woman into custody but he too was then beaten by the police (the second officer was there as well). Sara and the soldier were arrested.
That afternoon a corporal from the battalion went to the area to discuss the arrests with the officers. Unfortunately, one of the police officers pistol whipped and fired shots at him. The corporal fled but was eventually caught. Rumors spread that he was killed, leading many of the battalion to start discussing what to do. The corporal was later freed but this did not dampen the soldiers' already agitated state. Other rumors of mistreatment continued to spread. The battalion major, who was white, ordered the men into formation and ordered them not to do anything rash. However, at this point a soldier fired a smuggled gun in the air and yelled that a mob was approaching the camp. All discipline was lost at this point, as the men feared for their lives. They grabbed rifles and ammunition (which the Major had ordered be taken away earlier in the evening) and lined up in formation and started to march towards Houston.