A schoolboy had already died before he was struck by an unmarked police car after he wandered on to a motorway into the path of traffic, it was disclosed today.
Scott Turner was hit by a number of vehicles on the M23 near Crawley, West Sussex, in the early hours of Sunday morning.
The 15-year-old, of South Way, Burgess Hill, had been at a family celebration, where it was alleged he rowed with his father before walking off.
The Independent Police Complaints Commission (IPCC) said it had concluded its assessment of the crash and referred the investigation back to Sussex Police.
Inquiries found that Scott's mother called police to report him missing at 1.46am.
Three minutes later, police received calls from two separate motorists saying they had hit a pedestrian on the M23.
At 1.57am, medics in an ambulance - which had been to another accident and was taking people to hospital - reported that they also believed they had collided with a body.
Then an unmarked police car which was following the ambulance was also believed to have struck the pedestrian, the IPCC said in a statement.
The case was referred to the IPCC because of the involvement of the police car, but the watchdog said it appeared Scott had already died before the police car became involved.
IPCC commissioner for the South East Mike Franklin said: "This is a terrible incident and I cannot begin to imagine what Scott's family is going through at the moment.
"The police are investigating the collision and I would urge anybody who witnessed the incident to contact them so that they can establish exactly what happened and why.
"We have looked specifically at whether the police car involved in the collision could have played any part in Scott's death.
"Having examined the various timings involved and looked at the information provided by road collision experts who went to the scene, it appears that Scott had already died by the time the police car became involved.
"If any new information comes to light which suggests that officers could have prevented the collision then it should be re-referred to the IPCC but, based on the evidence available at the moment, I am content to allow Sussex Police to take their investigation forward without further input from us."
Hundreds of people have joined groups on Facebook which have been set up in tribute to the teenager.
One message written by Laura Ann Chaitow said: "Apparently he was at a wedding and he had an argument with his dad, so went on a walk."
Another poster, Jessica Lansdall, wrote: "We are all going to miss you so much - you were much loved."
A further message, from Adam Bartholomew, read: "You had so much ahead of you, it is such a shame. You will be dearly, dearly missed my friend, love you lots."
The motorway was closed for more than eight hours as officers investigated the incident between junctions 10 and 10a.
A post-mortem examination is not expected for the next few days and no arrests were made.
Teachers at Downlands Community School in Hassocks, where Scott was a pupil, said he "had a ready smile which endeared him to staff and pupils alike".
In a statement, they said: "Scott had only been at Downlands a year but was very happy and settled, and was polite and courteous to staff.
"He very quickly made new friends and was a popular and well-liked pupil at the school."
Police appealing for information urged witnesses to call 0845 6070 999, quoting Operation Harlington.Reuse content