Humberside Police are appealing for information about an incident in Brigg yesterday (Sunday, July 5).
The force says an investigation has been launched to trace the driver of a vehicle "which collided with a pedestrian" at the Monument roundabout in the early hours of Sunday morning.
"However, the driver of the vehicle did not stop and we are now working to establish the circumstances of the collision," police say.
The force, which was contacted by ambulance crews at 12.50am on Sunday, is keen to speak to anyone who was in the area at the time, or believes they may have seen the man prior to the collision.
The force says it is particularly keen to speak to the driver of a white van which was seen driving towards Wrawby around the time of the collision.
Anyone who can help is asked to call 101, then quote log number 50 of July 5.