his party on the Oregon Trail; the animal wandered into a Brulé Lakota camp. A Miniconjou Sioux named High Forehead killed the cow for food. The Mormon farmer reported the cow as stolen to army officers at Fort Laramie. The fort's commander sent out an inexperienced officer, Lt. John Lawrence Grattan—said to be contemptuous of the Indians—to arrest High Forehead. But under the treaty of 1851, such matters related to livestock and relations with settlers were supposed to be handled by the Indian Agent, who was due to arrive soon. Grattan vowed to take the wanted Indian "at all hazards" and took along 30 men and artillery. He pressed the chief to surrender the Sioux man. One of his soldiers shot the chief, Conquering Bear, in the back and killed him. In the ensuing battle the Sioux killed Grattan and 29 of his men. One soldier survived the fighting but died later in the Fort Laramie hospital. President Franklin Pierce vowed to avenge the Grattan Massacre, as it was called by the press. The War Department appointed Harney to command, with instructions to "whip the Indians." In the ensuing debate, Grattan was blamed for the fracas in which he was killed. Harney Expedition The Harney expedition finally set out in August 1855. On September 1, 1855, the expedition caught up with a Sioux encampment along the Platte River in a place known as Blue Waters. Harney sent a regiment in a long night flanking maneuver to set up a blocking position against which he would drive the Sioux. The flanking maneuver was led by Lt. Col. Philip St. George Cooke and Capt. Henry Heth. Harney moved up in the morning to drive the Sioux against Cooke and Heth. He first attempted to parlay with the Sioux chief, Little Thunder, but his demands to hand over the men responsible for the Grattan attack were rebuffed. The Sioux felt justified in having killed Grattan and his men, as they had shot first. During the parlay, several Sioux braves discovered Cooke's men. Battle Upon the Sioux discovery of Cooke's men, Harney opened the fight by attacking the Sioux camp. Some of the Sioux took refuge in caves along the river. Harney had his men fire into the caves, where they killed many women and children. A large group of mounted warriors rode toward an escape route away from Cooke's and Harney's forces, but