Tecumseh, now about eighteen years old, became a warrior under the tutelage of his older brother Cheeseekau. Tecumseh participated in attacks on flatboats traveling down the Ohio River, carrying waves of immigrants into lands the Shawnees had lost. He was disturbed by the sight of prisoners being cruelly treated by the Shawnees, an early indication of his lifelong aversion to torture and cruelty for which he would later be celebrated. In 1788, Tecumseh, Cheeseekau and their family moved westward, relocating near Cape Girardeau, Missouri. They hoped to be free of American settlers, only to find colonists moving there as well, so they did not stay long.