PRESCOTT, Ariz. -- A Greyhound bus passenger who appeared to be impaired died Friday following an altercation with an off-duty driver after the vehicle broke down in north-central Arizona, authorities said.
Yavapai County Sheriff's officials said the name of the 53-year-old man was being withheld until his family could be notified.
An autopsy was scheduled to determine the cause of death and sheriff's officials also were awaiting results of a toxicology test on the man.
Deputies were called around 2:45 a.m. Friday about a disorderly passenger who appeared to be impaired by alcohol, drugs or medication on the bus bound for Flagstaff.
They reported finding an unconscious man lying outside the bus along Interstate 17 and he was pronounced dead at the scene.
Deputies interviewed the bus driver, the off-duty driver and several of the nearly 50 passengers.
They told authorities that after the bus was stopped by mechanical issues, the passenger began arguing with the driver and allegedly tried to assault him.
The off-duty driver reportedly intervened and the passenger collapsed inside the bus.
Sheriff's officials didn't release the names of the driver or the off-duty driver.
They said it was unclear if the confrontation resulted in the man's death or other factors were involved, but no arrests have been made in the case.
A call to Greyhound for comment on the incident wasn't immediately returned Friday afternoon.