BOX ELDER, S.D. (AP) — South Dakota authorities have released the names of two people from Arizona killed in a motorcycle crash with a semi-truck in Box Elder.

The South Dakota Department of Public Safety on Sunday identified the two killed as 54-year-old James Bradley, who was driving a 2005 Harley-Davidson motorcycle, and passenger 45-year-old Deanna Bradley, both of Parker, Arizona. Both were wearing helmets.

Two people from San Diego on another Harley-Davidson were injured. The driver and passenger on that cycle suffered minor injuries. Neither was wearing a helmet.

Authorities say the two motorcycles were westbound on Highway 1416 Thursday when they failed to stop at a stop sign at an intersection and collided with a semi that was turning onto the highway.

The truck driver was not hurt.

The South Dakota Highway Patrol is investigating.