A man has been arrested on suspicion of murder after a body was found on the M20 near Ashford, Kent Police have said.
The London-bound M20 was closed for more than 20 hours after the body was found just after 6pm on Tuesday.
The person was pronounced dead at the scene.
Officers investigating the death had been searching for a silver Nissan Qashqai and a man attended a Kent Police station on the evening of Wednesday 21 February with the vehicle, police said.
The man was formally arrested on suspicion of murder and remains in custody, a police spokesperson said.
Officers from the Serious Collision Investigation Unit are working with detectives from the Kent and Essex Serious Crime Directorate to establish the circumstances surrounding the death.
The incident caused hours of delays with between six and seven miles of queues stretching back to junction 11 and a diversion was in place.
The road reopened shortly before 3pm on Wednesday.
An accountant from Ashford told of his shock at the scene he saw while driving on to the coastbound stretch of motorway at about 6.20pm on Tuesday, while emergency services were on the opposite side of the road.
The 21-year-old, who asked not to be named, said: “As I entered the motorway I expected to see a crash, when I suddenly realised that it wasn’t and unfortunately it appeared to be a body lying in the central lane with police and ambulance staff around it.
“Because of the torches being shone by police [I could see] it appeared that the body had been struck by vehicles.
“It was very shocking. It is not a sight I would want anyone to witness.
“My condolences are with the family of the deceased.”
Police are still appealing for drivers who were on the road at the time to check their vehicles for signs of a collision, and for anyone with dash cam footage or who saw the Nissan Qashqai with the registration KY15 WWX at the time of the incident to come forward.
Press Association contributed to this report
