A body found on the M1 motorway appears to have been run over several times, police said.
A stretch of the motorway has been closed in Northamptonshire following the discovery some time before 3am on Tuesday
Sergeant Tony Hopkins told BBC Northampton the body is believed to be male.
He told the station it had been "travelled over by several vehicles" and investigations were continuing.
Police said the road was expected to remain partially closed for most of Tuesday following the discovery.
Highways England said the "serious incident" closed the northbound carriageway between junction 16 near Northampton and junction 18 near Rugby.
Northamptonshire Police said: "Motorists are advised to seek alternative routes and diversions will be in place."
Anyone with information should contact police on 101 or Crimestoppers anonymously on 0800 555 111.