Missing Kyle Vaughan's family 'desperate' for news of him
The family of missing Kyle Vaughan from Newbridge, Caerphilly county, say they are desperate to know what may have happened to him.
The 24-year-old, who has diabetes and needs insulin, disappeared on 30 December and his family have been told he is feared dead.
Eight people have been arrested in a police murder investigation.
His cousin Beckie Imm said: "His mum's still waiting for that call or text."
She added: "The more time that goes on, the more worrying it is.
"And we'd like to know who he is bothering with, who's seen him, who's heard from him. Where did you go? How was he feeling?
"It's all relevant to build up a bigger picture of what's happened to him possibly," she said.
On 30 December, Mr Vaughan's silver Peugeot 306 was found abandoned on the A467 near Risca. It had been in a collision, but police do not know whether he was driving it at the time.
A 27-year-old woman and a man aged 28, both from the Cwmfelinfach area, were arrested on Tuesday and remain in custody on suspicion of murder.
Earlier in the inquiry, a 24-year-old man from Blackwood and another man, aged 27, were also arrested on suspicion of murder.
Two other men, aged 21 and 15, were also arrested on suspicion of assisting an offender, while a 62-year-old Newbridge man and a 22-year-old Newbridge woman were arrested on suspicion of perverting the course of justice.
All six have been bailed.
The man leading the inquiry into Mr Vaughan's disappearance, Det Insp Peter Jones from Gwent Police, said: "It's rare that we would treat such a disappearance as a murder investigation.
"But because of information known to the investigation team and that we've discussed with Alan and Mary - Kyle's parents - I'm now treating this disappearance as a murder investigation."
Mr Vaughan's family say the last few weeks have turned into a nightmare for them and they have asked anyone with information to go to the police.
He is 5ft 8in (1.72m) tall, slim, with short dark hair and brown eyes.
It is believed he was wearing a dark beanie hat, a dark t-shirt, three-quarter length denim shorts, white trainers and a gold chain.
He was known to wear a gold neck chain with a cross. He has a distinctive tattoo of a pair of flaming dice on his inner left forearm, as well as tattoos on his right leg.
Gwent Police have asked anyone with information to call 101, 01633 838111 or Crimestoppers anonymously on 0800 555111.