However, the Mormon population grew and the Indian population declined through disease and destruction of food resources. Mormon leaders moved to disrupt the Mexican trade in horses and people (a law against the Mexican slave trade was passed by the territorial legislature in 1853), thereby undermining Wakara's wealth and power. Wakara grew to distrust the white settlers as they encroached on Ute hunting lands and began resisting that encroachment.
In July 1853, while Wakara and his followers were camped on Spring Creek near Springville, an altercation over trade took place in which a Mormon settler killed a Ute and wounded two others. Wakara demanded the killer be brought before him. His request was refused. This incident precipitated the Walker (Wakara) War.
The war was mainly a series of raids led by Wakara on the Mormon settlements. Utes attacked Fort Payson; the Mormon Nauvoo Legion responded. During the next ten months fewer than twenty whites were killed; many more Utes died, including nine "shot down without one minute's notice," after they came into a Mormon camp looking for protection and bread.