Questions need to be asked over the police response to a car crash tragedy, a former Welsh crime commissioner has warned - and said "alarm bells" should have rung when five young people went missing.
Eve Smith and Darcy Ross, both 21, and Rafel Jeanne, 24, died in the collision, while Sophie Russon, 20, and Shane Loughlin, 32, remain in a critical condition after a Volkswagen Tiguan they were in left the A48(M) in Cardiff and hit trees in the St Mellons area of the city.
Officers believe the car was involved in a collision and left the road some time later, but further investigations are needed to establish an exact time.
The group had been to a social club in Maesglas, Newport, on Friday and are thought to have then travelled 40 miles to the Trecco Bay area of Porthcawl.
After failing to go home, the five were reported missing by their families.
Ex-barrister and author Winston Roddick described it as an "unusual case", saying "alarm bells" should have been ringing sooner when parents contacted police.
The former North Wales Police and Crime Commissioner said the response to families was "not quite right" as there had been no activity on any of the group's mobile phones.
He said: "Maybe there should be questions asked and some effective inquiry made to see whether any one or more of them could be traced. If not, then the question mark becomes bigger."
Family and friends have hit out at the police reaction after it took 46 hours to find the five in the wreckage off a busy road in St Mellons, Cardiff.
The first call reporting the victims as missing was made to police at 7.34pm on Saturday, while further reports were made up until 5.37pm on Sunday.
Hundreds of people took part in searches but Gwent Police did not issue a public appeal for help until 11pm on Sunday.
David Ford, IOPC director, confirmed that the Independent Office of Public Conduct (IOPC) had launched an investigation into the police response.
He said: "After careful assessment of referrals from Gwent Police and South Wales Police, we have decided to independently investigate how police responded to the missing person reports.
"We will be examining what information police had, the grading given to any risk assessments and the steps taken by police to locate the missing people prior to the Volkswagen Tiguan being found just after midnight on Monday.
"We will also consider what communication took place between the two forces and whether police action was appropriate and followed relevant policy and procedures."
Rafel's former school paid tribute to him, describing him as a "popular" and "joyful" pupil who excelled at rugby.
The Welsh-speaking school Ysgol Glantaff, said: "It is with great sadness that we hear of the loss of one of our dear, former pupils Rafel Jeanne, who was cruelly and unexpectedly taken this week.
"Rafel was a joyful pupil, full of life and energy at school, popular within his year group and a very sincere friend who was well respected among his classmates.
"He contributed regularly to school activities, starring as a member of rugby teams, at the National Stadium winning the Welsh Cup in 2013 and travelling with the school's 7-a-side squad to compete in the Rosslyn Park finals in 2012.
"His energetic, enthusiastic approach and warm smile attracted people to him and marked his character.
"Rafel was a popular and happy pupil, keen to support others, indeed seeing his development during his time at school was proof of his maturity and consistent effort within the school community.
"We send our sincere condolences to Rafel’s family and friends throughout the city and beyond, as we dearly remember a joyful and dear pupil whom we are delighted and proud to know as a member of teulu Glantaf."
Meanwhile, a friend of Mr Loughlin posted: "I'm so proud of us all pulling together out there searching for our dear friends last night.
"It's heart breaking what's happened to Rafel Jeanne and those two girls. My body is still shaking and I can't stop being sick (at) the thought of them all there all of that time."
Ms Smith's death comes eight years after her sister Xana Doyle, 19, was killed in a car crash. The driver, who was twice the drink-drive limit, was prosecuted and Ms Smith took part in a Sky TV documentary about the incident and campaigned for tougher sentences.
Another sister paid tribute to her in a Facebook post.
"I know you're safe up with there with our beautiful sister Xana but I was never ready to let you go, my body is aching without you," she said.
In a statement, Ms Smith's family asked for their privacy to be respected.
They added: "We want to allow Gwent Police and South Wales Police the time and space to investigate the matter in a thorough and professional way and to enable the Independent Office for Police Conduct thereafter to come to their own conclusions."
Gwent Police's Assistant Chief Constable Mark Hoborough and South Wales Police's Assistant Chief Constable Jason Davies said their thoughts are with the victims' families.
