One man is dead and another man is injured after a one-vehicle rollover accident seven miles north of Kaycee in Johnson County.

Wyoming Highway Patrol investigators say 23-year-old David Niffenegger and 26-year-old Michael Mondeau, both of Kaycee, were moving northbound on Wyoming Highway 196 on Sunday when their 2005 Dodge Ram pickup left the roadway and flipped several times after failing to negotiate a left turn.

Niffenegger was ejected from the pickup and was found dead at the scene, while Mondeau was partially ejected from the vehicle and was transported to a hospital in Buffalo. Both Niffenegger and Mondeau weren't wearing seatbelts.

Authorites say they're still trying to determine who was driving the vehicle.

Sgt. Stephen Townsend with the Wyoming Highway Patrol says the accident remains under investigation. Townsend says troopers are trying to determine whether alcohol and excessive speed were contributing factors.