An investigation is underway into the circumstances of a car crash which left three people dead and two others seriously injured.
All five people, three women and two men, had last been seen in Cardiff in the early hours of Saturday after a night out.
The women, Sophie Russon, 20, Eve Smith, 21, and Darcy Ross, 21, were last seen in Cardiff in the early hours of Saturday having travelled there from Porthcawl.
They had made the trip in a Volkswagen Tiguan with two men, Rafel Jeanne, 24, and Shane Loughlin, 32, both from Cardiff, who were also reported as missing.
On Monday, a police spokesperson said the VW Tiguan had been recovered just after midnight in the St Mellons area of Cardiff.
Police believe the car was involved in a road traffic collision and came off the A48(M) but it is not clear exactly when that happened.
The A48(M) has been closed in both directions, near to the Cardiff Garden Centre, by the police.
Photographs from the scene show large green fencing and tarpaulin has been erected around the crash site, which is among trees.
People have also started arriving to leave floral tributes to those who died.
Meanwhile, Thomas Taylor, 47, from the Rumney area of Cardiff, has been arrested at the scene for prevention of breach of the peace, police said.
It is understood he was arrested after being asked to leave the area.
Speaking before he was arrested, Mr Taylor, a film and TV extra, told the PA news agency: “When I heard the reports, I just couldn’t believe it could be possible that a car could come off and no-one know they were there,” he said.
“I still don’t understand it.
“It worries me, and I feel for the families because from what I can see from the reports they did have a feeling something was wrong and they were flagging it up. Their instincts were correct.
“I have some fears that perhaps when the reports came they had gone missing people thought: ‘Oh, it’s just a night out’.
“It’s natural they might have disappeared for a bit, but the families’ instincts are right.”
Gwent Police said the two injured people were being treated in hospital for serious injuries.
“Specialist officers are supporting the families of those involved and enquiries are ongoing,” a force spokeswoman said.
“The case has been referred to the IOPC in line with normal procedures.”
An IOPC spokesman said: “We can confirm that Gwent Police have advised us that they are making a referral in connection with this tragic incident and we will carry out an assessment in due course to determine what further action may be required from us.”
Later, South Wales Police said that at 12.15am on Monday officers were called to a report of a car being located off the A48(M).
“South Wales Police is carrying out an investigation into the road traffic collision to establish what happened,” a force spokesman said.
“We would like to thank the public for their patience and their cooperation whilst the road is closed. Our thoughts are with those affected by this incident.”
