WINTERSET, IA (KELO.com) — The Iowa State Patrol is investigating an accident that left one teen dead and three other teens injured. The accident occurred early Sunday morning near Winterset, Iowa, southwest of Des Moines. The online crash report reads the 17-year-old driver of a GMC Sierra was speeding on a gravel road, lost control and went into a ditch. The vehicle then hit a tree. The driver was killed. Three teen passengers were injured. No one was wearing a seatbelt and alcohol is suspected.