A search is under way for three teenage boys who are believed to have run away from a VisionQuest wagon train on horseback, then fled in a car stolen from Salina, authorities say.

The juveniles left the wagon train late Tuesday, said Sevier County Deputy Kim Sorenson. The treatment program that operates the wagon train is based in Tucson, Ariz.The boys, age 14, 15 and 16, all from San Diego, were participants in one of two Vis-ionQuest wagon trains traveling through Utah, said Tim O'Sullivan, director of mobile programs. Their group was located at Axtell, about five miles north of Salina.

Three horses were found near Salina, and authorities learned that a 1956 black and white Chevrolet had been stolen early Thursday, Sorenson said.

The car's owner, who was not identified, told investigators he had left a .22-caliber Ruger semiautomatic pistol loaded with four or five rounds in the car.

The car was found abandoned later Thursday on I-15 near Beaver, about 70 miles to the south, but the weapon was gone and the boys remained at large, said Sevier County sheriff's dispatcher Jim Roberts.

The car, weapon and the boys' names also have been registered with the National Crime Information Center, the deputy said.