The younger brother of a teenager who went missing on the Isle of Wight 19 years ago has said he is hopeful of finding out what happened to him.
Damien Nettles vanished, aged 16, after a night out with friends in November 1996. His body has never been found.
James Nettles has returned to the island from his home in the US to take part in a TV documentary. He said the family had been "left without closure".
Last month police said the case would remain open.
The last confirmed sighting of Damien was on CCTV in a chip shop off Cowes High Street late on Saturday 1 November 1996.
James Nettles, who was aged 12 at the time, said he remembered Damien's disappearance as a "dark era".
"I was old enough to remember the chaos which ensued. It's always been difficult to get solid fact - people don't like to talk about it."
He has returned to the Isle of Wight from his new home in Dallas, Texas, to take part in a documentary series being shot for BBC Three.
"I don't believe we've had an investigation as in-depth as this. I'm very hopeful. It's made me quite optimistic about it," he said.
Producer Alys Harte said: "This is a case which has so many unanswered questions and unknowns. After 19 years there has been a slow build up of rumour and speculation.
"It is a very long time for a family not to know what had happened."
In November Hampshire Constabulary renewed its appeal for information.
The force said 1,134 people had so far been involved in the investigation - either as investigators, witnesses or people of interest - and 357 witness statements had been taken.
The BBC Three documentary is due to be screened in March.
The BBC production team is appealing for anyone with information about what happened to Damien Nettles to get in touch - in confidence - on email@example.com or 07851002225.