A man who died shortly after the car he was in was found in a roadside ditch had been treated for suspected hypothermia at the scene.
The vehicle was spotted by a member of the public off the A426 Lutterworth Road near Dunton Bassett in Leicestershire on Monday morning, and is believed to have been there overnight.
A male was found inside by emergency crews but was not trapped, according to the fire brigade.
The police have closed the road and are investigating the scene in a bid to work out exactly what happened.
A Leicestershire Fire and Rescue Service spokesman said: "A call was received from East Midlands Ambulance Service to assist at a road traffic collision where a car had gone into a ditch.
"Crews arrived on scene to find no persons trapped.
"It was believed that the car had been there overnight, and ambulance crews were treating the casualty for suspected hypothermia."
Weather station readings showed temperatures in the surrounding area had been down to between 2C-3C above freezing overnight.
A spokeswoman for Leicestershire Police said: "We were called at 7.43am this morning following a report of a car in a ditch on the side of the A426, Dunton Bassett.
"When we arrived, it was found there was a male in the car and he was pronounced dead at the scene.
"Work is being carried out to establish the circumstances of the incident.
"The road is currently closed and likely to be for a number of hours."