SALINA, Utah (AP) — Utah state troopers say four members of a Nebraska family were killed and a fifth was injured after their pickup truck rolled several times and crashed on a highway in rural, central Utah.

Utah Highway Patrol Sgt. Todd Royce says a husband and wife, their two daughters and an infant grandson were not wearing seatbelts and were thrown from the truck in the Thursday morning crash.

Royce says the baby, the 46-year-old husband and two of the adult women died at the crash site. A third female was flown to a Salt Lake City hospital in critical condition.

Royce says the family’s identities won’t be released until other family members are notified.

Investigators say fatigue may have caused the crash.