GREGORY, S.D. - A 15-year-old girl was killed and another suffered life-threatening injuries in a single-vehicle crash west of Gregory on Sunday morning.

According to the South Dakota Department of Public Safety, the crash happened on April 13 at 10:13 a.m. along U.S. Highway 18, about four miles west of town. Authorities say the injured teen, who was driving a 2001 Chevrolet Blazer, veered onto the shoulder, which was under construction. When she tried to re-enter the highway, the vehicle spun, entered the south ditch, and rolled.

The passenger, who was not wearing a seat belt, was thrown from the vehicle. The driver, who was wearing a seat belt, was also seriously injured.

Both girls were airlifted to a hospital in Sioux Falls, where the passenger later died from her injuries.

The South Dakota Highway Patrol is investigating the crash. All information released so far is considered preliminary.