Watch: Aerial pictures show scene of deadly Cardiff car crash
The mother of a survivor of a car crash in Cardiff said her daughter called out for help for two days next to her dead friends.
Sophie Russon, 20, is in a critical condition in hospital after the crash in St Mellons, Cardiff, Wales.
Her friends, Eve Smith, 21, and Darcy Ross, 21, along with Rafel Jeanne, 24, died in the crash.
Another man, Shane Loughlin, 32, is also in a critical condition in hospital.
The five people went missing on Saturday morning after a night out and their Volkswagen Tiguan was not found by police until two days later.
The two police forces investigating the crash, South Wales Police and Gwent Police, have referred themselves to the Independent Office of Police Conduct (IOPC).
Sophie's mother, Anna Certowicz, 42, said her daughter was lying for 46 hours next to her three dead friends.
Ms Certowicz told The Sun: “I drove past three times. Sophie was 20 yards away lying there scared, next to her friends who were dead.
“But I didn’t see her because of the trees and there was a dip. She must have thought she was going to die. She was calling out at times but no one could hear her."
She had previously criticised the police for taking two days to find the missing five people.
She said she spent Sunday night driving around the Gwent and Cardiff areas in a desperate search for her daughter - and said police officers told her to "stop ringing" the station for updates.
Certowicz said: "They didn't seem to care. I had to drive to Cardiff to knock on doors myself. They just didn't seem to think it was worth investigating. It was so frustrating.
"I think they assumed that Sophie was hungover somewhere, but she's a sensible girl who works in a bank and hasn't taken a day off for three years.
"She's not someone who's out clubbing in Cardiff all the time. On Friday nights she's more likely to be babysitting so other people can go out.
"She wouldn't just vanish like this unless something was wrong.
"The police asked me to stop ringing but at the end of the day I'm a mum I'm going to worry. Her little sister is worrying too, she's only 13 and she's wondering where Sophie is."
The five had been to the Muffler social club in Maesglas, Newport, on Friday night, and were due to travel 40 miles to the seaside spot of Trecco Bay in Porthcawl.
Their families are angry that it took police two days to discover their vehicle, which came off the A48 dual carriageway into woodlands.
The three women in the crash all grew up in Maesglas and were friends since their days at school.
Both South Wales Police and the neighbouring Gwent force, who were leading the missing persons investigation prior to the discovery of the car, said they have referred themselves to the IOPC “in line with normal procedure”.
An IOPC spokesperson said on Tuesday: “We are urgently carrying out an assessment of referrals received yesterday from Gwent Police and South Wales Police to determine what action may be required from us.”
Watch: Tributes paid to three people killed in Cardiff car crash