A 23-year-old man has been arrested and released under investigation after a car overturned in Swansea.
No other vehicles were involved when a Mercedez-Benz A class flipped over in Clwyd Road in the Penlan area of the city at 4.07am on Saturday, October 3.
One of the occupants of the car, a 21-year-old man, suffered serious injuries and was taken to University Hospital of Wales in Cardiff in a critical condition.
On Saturday, October 3, a spokesman for South Wales Police said: "Officers are keen to identify a second man who is also believed to have been in the car but left the scene prior to their attendance.
"Members of the public are thanked for their patience, while investigation work is carried out at the scene and for their patience during the road closures."
The roads around the scene of the incident, which happened near to Clywd Road's junction with Penderry Road, remained closed for much of the morning as investigations were carried out.
Police have now confirmed that a second person from the vehicle was arrested and released under investigation.
A spokeswoman for South Wales Police said: "We continue to appeal for witnesses to the incident, or the manner in which the green Mercedes-Benz was being driven prior to the collision, are asked to please contact South Wales Police on 101 and quote occurrence 2000360836."
