ST. LOUIS (KMOV) -- A 13-year-old boy was killed Saturday after he was trapped under the bed of a dump truck in St. Clair County, Ill., authorities said.

The St. Clair County Sheriff's Department said the accident happened just after 12:30 p.m. near the intersection of Stolle and Triple Lakes roads in Dupo.

The department said the driver of the truck stopped to ask Ryan Henneman and a friend, who were riding their bicycles, to help him level a load of gravel he had just picked up about a half-mile from the accident scene at Falling Springs Quarry Co.

Henneman was standing on the left side of the truck when the driver began adjusting its hydraulic system. The truck's bed tipped over, trapping the teen, officials said.

The driver of the truck was taken into custody on a warrant from another state, though authorities would not elaborate.

Henneman was pronounced dead at the scene.