Two men from the Bargoed area died when a car they were travelling in crashed into a telegraph pole in Merthyr Tydfil yesterday, October 11.
A 20-year-old man has been arrested on suspicion of causing death by dangerous driving after a teenager was one of two people who died in the crash that occurred around 10.30pm on Aberdare Road in Georgetown.
The two men who died in the crash were named as Rhys Jones, 18, and Ryan Gibbons, 20, by South Wales Police.
There were five men in the the white Seat Ibiza, aged between 18 and 2,0 and a third casualty remains in critical condition in University Hospital of Wales in Cardiff.
A fourth injured teenager is in Prince Charles Hospital in Merthyr, suffering from minor injuries.
Police are keen to speak to anyone who was travelling around Merthyr town centre on Sunday evening, who may have seen the vehicle prior to the collision.
Sergeant Gethin Hewer said: “ Our thoughts are with the families of both these young men at this traumatic time. The families are being supported by specially trained family liaison officers and we are continuing the investigation to find the cause of the collision.
“We are particularly keen to hear from anyone who may have seen the white Seat Ibiza travelling around the Merthyr Tydfil area prior to the collision.”
Anyone with information about the collision can call South Wales Police on 101 quoting reference number 1500377114.
There was no other vehicle involved in the incident.