Police in Devon are investigating the possibility that a 17-year-old boy was seriously hurt after "roof surfing" on top of a car.
Emergency services called to Maer Road in Exmouth found the boy with life-threatening injuries and ordered an airlift to hospital in Plymouth.
Police arrested the driver of the car, who is also 17, and later bailed him.
A police spokesperson said: "At this time it is still not very clear what has happened in this incident."
Anyone who witnessed anything in connection with the incident is being asked to contact the police.