Three trucks including an articulated lorry unwittingly ploughed into a body that fell on to a motorway from a bridge.
The corpse was found on Tuesday afternoon on the eastbound carriageway of the M25 at junction 9, near Leatherhead in Surrey.
Officers were called at 3.04pm by drivers who made the gruesome discovery.
The currently unidentified person is believed to have fallen from an overhead bridge on to the motorway, and police are keen to speak to anyone who saw what happened.
Detectives from Surrey Police said they were particularly keen to trace the driver of a yellow Mercedes Sprinter truck, a blue goods vehicle and a white Volvo articulated truck with a trailer who are all thought to have struck the body on the motorway before carrying on.
A force spokeswoman said: "When the body was on the carriageway it was struck be several vehicles. It's likely that the motorists didn't realise what had happened. Officers are particularly keen to trace the drivers of these vehicles."
She added "Officers are investigating the circumstances of this incident and inquiries are ongoing."
Anyone with information is asked to call 0845 125 2222.
