On July 13, 1859, Juan Cortina saw Brownsville city Marshal Robert Sheers arrest and beat an elderly man who had been a ranch hand at his mother's ranch. Cortina approached the marshal, questioning his motives, before shooting him twice after he refused to release the man. The first shot reportedly missed Sheers, but the second struck his shoulder, causing him to fall to the ground. Cortina and the elderly man rode off on a horse. The following year, Cortina returned with troops, executing four Anglo men and simultaneously releasing several Mexican prisoners. He then issued a proclamation explaining his reasons for the attack.