A passenger traveling on a bus across Canada’s vast Western plains stabbed, gutted and decapitated a man seated next to him in an unexplained attack, a witness told media Thursday.

The victim had been sleeping before he was repeatedly stabbed in the chest by a man with a large knife, witness Garnet Caton told public broadcaster CBC.

The other 35 passengers and driver were jolted by “blood-curdling screams” and fled. “He must have stabbed him 50 times or 60 times,”