(AP) — The Stanton County sheriff’s office is investigating what led a man to fall or jump from a moving vehicle and suffer serious injuries when his head hit the pavement.

Authorities say 60-year-old Patrick Prather, of Norfolk, suffered a serious head injury when he fell or jumped from a moving semitrailer on Northeast Industrial Highway near Stanton in northeast Nebraska.

Authorities say Prather was standing on a semi being driven by a 23-year-old Madison man when Prather fell or jumped and struck his head on the highway. He was treated at the scene, then flown to Mercy Medical Center in Sioux City, Iowa.

No charges or citations have been issued.