Authorities are investigating a Greyhound bus crash in rural Utah that killed a 13-year-old girl and injured 11 others. Utah's Highway Patrol says the bus headed to Las Vegas crashed Sunday night off Interstate 70 west of the Utah city of Green River. The bus went off the highway shoulder into a steep wash and stopped about 200 feet away from the road. The bus driver and two passengers were airlifted in serious condition to hospitals in Grand Junction, Colorado and Provo, Utah. Troopers say they're still investigating the cause of the crash but one passenger reported the driver appeared to have a medical issue.