BOISE, Idaho (AP) — A 2-year-old boy in a vehicle that plunged into Arrowrock Reservoir in southwest Idaho has died. The Ada County Coroner's Office says Riley Lutton died Monday at St. Luke's Medical Center in Boise. The cause of death is pending. Idaho State Police say that on Friday a vehicle driven by 31-year-old Lawrence Lutton of Lowden, Washington, went off Arrowrock Road and into the reservoir. Riley Lutton was flown to the hospital and another child in the vehicle and Lawrence Lutton were driven to the hospital by another motorist. Police continue to investigate.