Derbyshire police are appealing to hear from the driver or passengers of a car that was seen to stop near the scene of a fatal collision on the A38 last night.
Officers were called to a stretch of the southbound A38 between Ripley and Kilburn, following reports that there was a body in the road.
A body was found by officers a short time later and an investigation has been ongoing since then.
There are not believed to be any suspicious circumstances but officers need to hear from as many witnesses as possible while inquiries continue.
A Derbyshire police spokesman said: “In particular, we want to trace the occupants of a car that was seen near to where the body was found.
“We understand that one of the occupants of the car got out for a short time, before then getting back in and driving off.
“We’re not sure precisely what time this car would have stopped but if you were driving along the A38 last night and you did pull over, we want to hear from you urgently.
“The incident was reported to us just after 11pm last night and the carriageway was closed in both directions until about 8am today.
“It was closed again just before noon so our collision investigators could continue their work and it will remain shut for some time.
Diversions are in place and we would urge people travelling in the area to plan extra time into their journeys.”
If you have any information that could help our officers, call Sergeant Scott Riley from the Collision Investigations Unit on 101, quoting incident 983 of August 3.