The mother of missing Isle of Wight teenager Damien Nettles has described how she believes her son was murdered over a cannabis debt.
Valerie Nettles has always dismissed theories that her son fell into the sea after a night out in West Cowes on 2 November 1996 when he was aged 16.
She told BBC News she believes her son was beaten to death by a drugs gang.
Three people remain on bail over the death. Detectives are keeping an open mind about Mrs Nettles's claims.
Mrs Nettles, who now lives in Texas, said: "People said Damien probably fell in the sea but there has been more information that he fell foul of some people.
"I believe he was beaten to death. He wasn't into drugs but I wouldn't be surprised if he smoked a bit of cannabis with his friends. He was more into getting his hands on a bottle of cider."
She said: "Whatever happened, Damien did not deserve this. He was just a silly boy who got in the way and someone decided to teach him a lesson."
Mrs Nettles, who moved to the US after her husband had to move there for work, said despite Cowes's exclusive reputation there are people involved in the supply of drugs.
"A couple of these people have since passed away from overdoses so it's difficult to prove now, but there are still people around who have information about what happened," she said.
"We understand that someone involved with these particular people told them what they did to Damien."
In a desperate bid to encourage witnesses to come forward with information about her son's death, Mrs Nettles is hoping to offer a £10,000 reward.
The Nettles family, who previously lived in Woodvale Road, Gurnard, had wanted to offer a reward in conjunction with Hampshire Constabulary for some years, but said they had been dissuaded from doing so by the force.
"The police always said it would not be advisable because it would bring out more low-life scum with the same information they've already got," she said.
"But it's an avenue we've not been down before so if we don't do it we'll always regret it. If anyone is going to grass anyone up it'll be for money."
The reward will be paid for information which leads to those responsible for Damien's suspected murder being convicted and her son's remains found.
If the reward fails to deliver the required results, funds raised will be distributed to UK-based charities.
A private detective has been investigating Damien's disappearance since 2007.
The last confirmed sighting of Damien was on CCTV at Yorkie's fish and chip shop in Cowes High Street on a stormy night at about 23:45 GMT. There has been no trace of the accomplished musician since.
In 2010, Damien's case was changed by the police from that of a missing person to a suspected murder investigation.
In May last year, specialist teams using rafts combed the water and reed beds at Dodnor Nature Reserve, near Newport, but failed to find his body.
No evidence was found during a police search of a property at Marsh Road, in Gurnard, in November 2011.
Earlier this month, police said no further action would be taken against four men arrested in connection with Damien's disappearance.
But a 38-year-old man from Ryde, Isle of Wight, who was arrested on suspicion of murder, was re-bailed until 7 March.
A 35-year-old woman and a 44-year-old man, both from Cowes, who were arrested on suspicion of conspiracy to murder, had their bail extended until 7 March.
A Hampshire Constabulary spokesman said: "Although we have sufficient information to make arrests over an allegation of murder in 1996, detectives will keep an open mind about exactly what happened to Damien because a wide range of information has been received over the past 15 years."