Eve Smith was one of three people found dead at a crash scene in St Mellons shortly after midnight, sister Lauren Doyle said on Monday.
Along with two others – who have “serious” injuries – the trio had been reported missing on the weekend after reportedly attending a club in Maesglas.
A major police investigation has been launched into the fatal crash, and enquiries are “ongoing”, police said on Monday.
Fatal crash in 2015
Ms Smith, 21, is the sister of Xana Doyle, who died in Newport eight years ago when she was the passenger in a car being driven by Sakhawat Ali, who had been drunk and high on drugs when he crashed the vehicle.
Ali, then 23, of Harrow Road, was later sentenced to eight years and three months in prison for his part in the crash, while his cousin, Shabaz Ali, 21, of Ribble Square, who was a passenger, admitted one count of “aggravated allowing to be carried involving a fatal accident”.
At the time of Ms Doyle’s death, the Argus reported on tributes to the 19-year-old victim, including from Ms Smith, then 13, and her other siblings.
Police probe St Mellons crash
The crash in St Mellons this weekend followed desperate appeals from family members to find the three Newport women and two Cardiff men who had been reported missing.
Police later named the five-strong group as Ms Smith, Sophie Russon (20), and Darcy Ross (21), all from Newport; and Rafel Jeanne (24) and Shane Loughlin (32), from Cardiff.
According to police, the three women were last seen at about 2am on Saturday, March 4 in the Llanedeyrn area of Cardiff.
But it wasn’t until nearly 48 hours later that their car, a Volkswagen Tiguan, was discovered near a roundabout off the A48 in St Mellons.
Specialist officers are supporting the families of those involved and “enquiries are ongoing”, a Gwent Police spokesperson said.
Anyone with any information is asked to call police on 101, or send a direct message on social media, quoting 2300071791.