A 24-year-old man from Franktown died early Monday morning when his truck plunged off a cliff into Castlewood Canyon in Douglas County.

Terry Walker lost control of a black 1995 Chevy 3500 pickup truck in the southbound lane of Castlewood Canyon Road in Castlewood Canyon State Park at about 1:55 a.m., according to the State Patrol. The truck ran off the left side of the road and fell to the bottom of the canyon.

Walker was not wearing a seat belt and was ejected from the vehicle, according to investigators.

The State Patrol is investigating, trying to determine whether speed or impairment played a part in the crash.