The United States government purchased two million acres of the Indian Territory and in 1889 the region was thrown open to white settlement. The region soon developed serious law and order problems. Three deputy United States marshals, Chris Madsen, Heck Thomas and Bill Tilghman, who became known as the Three Guardsmen, were largely responsible for wiping out organized crime in Oklahoma. This included the hunting down Bill Doolin and his gang. Others dealt with included Red Waightman and Oliver Yountis.