Missing Kyle Vaughan: Man, 24, arrested on suspicion of murder
A 24-year-old man has been arrested on suspicion of murdering missing Kyle Vaughan.
Gwent Police have also arrested a 22-year-old woman on suspicion of perverting the course of justice.
The arrested pair, from Blackwood and Newbridge respectively, are being questioned in connection with the disappearance of Mr Vaughan.
Known as "Jabbers", Mr Vaughan, was last seen at his Newbridge home on 30 December and is now feared dead.
Senior investigating officer Det Supt Peter Jones said: "We want to reassure people that we continuing to make every effort to locate Kyle and to investigate the circumstances surrounding his disappearance."
His parents Alan Vaughan and Mary Lucas believe witnesses were "too scared to come forward".
They spoke of their ongoing "nightmare" as a major search for their son continues.
Both believe information vital to the police murder hunt is being held back by people fearful for their own safety.
The missing person inquiry took a more serious turn last Friday following the arrest of a 27-year-old man on suspicion of murder.
Two other men, aged 21 and 15, were later arrested on suspicion of assisting an offender.
All three were later released on police bail pending further enquiries.
A 62-year-old Newbridge man was also arrested at the weekend on suspicion of perverting the course of justice and later released on bail.
Rock music fan Mr Vaughan is believed to have been last seen alive in Caerphilly's Abercarn and Risca areas.
His family described him as a "larger than life, fun-loving young man" as they spoke for the first time since he went missing.
They said their lives had been "on hold" since 30 December, 2011.
They said: "We feel there are people out there who could hold information that is vital to this inquiry. It's also possible that there are people who know what's happened to Kyle but are too scared to come forward.
"We would ask those people to please help us to find our son, who is a family-orientated, larger than life, fun-loving young man who is deeply missed by his large family and loyal friends."
Mr Vaughan is 5ft 8in (1.72m) tall, with a slim build, and short dark hair and brown eyes.
He was known to wear a gold neck chain with a cross and has a distinctive tattoo of a pair of flaming dice on his inner left forearm as well as tattoos on his right leg.
On the night he disappeared, at approximately 23:45 GMT, officers found Mr Vaughan's car, a silver Peugeot 306, which had been involved in a collision.
Gwent Police have asked anyone with information to call 101, 01633 838111 or Crimestoppers on 0800 555111.