The body of a man found on the M1 in the early hours of the morning suffered "catastrophic" injuries after being run over at speed by multiple vehicles, police have said.
Investigators said they were investigating whether the man was a murder victim and if he was forced from a moving vehicle.
A stretch of the motorway near Northampton was closed for several hours after the body was found on the northbound carriageway between junctions 16 and 18.
It was reported to the police by a driver just after 2am on Tuesday morning, police said.
Detective Sergeant Tony Hopkins, from the collision investigation unit, said in an official statement: “We can confirm that the body is that of a man and that he appears to have come into contact with several vehicles on the M1.
“It may be an innocent accident or something more serious.
"The investigation team [...] will now work to determine the circumstances that lead to his death.”
In a filmed update, he said: “If I can use the word ‘catastrophic’ [it] would probably relay how this incident has been played out this morning with the amount of vehicles involved, the speeds of those vehicles and the types of vehicles — before we’ve been about to shut the motorway and prevent any further impact with the male that was on the road.
“He could have been on a vehicle, tried to exit a vehicle, [or] been forced from that vehicle. There are several lines of inquiry.”
Northamptonshire Police said they had identified the man from his fingerprints, but that he could not be identified until his family had been informed.
There was no obvious footpath near the incident indicating where the man had come from, police said.
The force has appealed to motorists who used the road on Tuesday morning to hand in dash-cam footage.
Sgt Hopkins said the man was found on an unlit stretch of road and that a driver could have believed they had hit an animal rather than a person.
Witnesses, or anyone with information, can police on 101 or 03000111222 if outside of the county.
