Tap above to watch full report by Martin Stew
Charity Crimestoppers has put up a £20,000 reward to help solve the decades-old mystery of what happened to Lee Boxell, the boy disappeared near his home in Cheam in 1988.
Lee's disappearance has haunted his family who are desperate to know what happened as he reaches his 49th birthday.
Rumours and speculation have shrouded his disappearance and, to this day, it remains a mystery about exactly what happened to him.
It was feared Lee may have been killed after witnessing child abuse at a teenage hang-out near his home.
"We're desperate for someone to come forward and tell us what happened to Lee which may ultimately help find his remains if he was murdered as we fear," said Lee's father Peter Boxell.
"There have been appeals for information over the years, but with Crimestoppers you can speak up completely anonymously.
"Once you've given your information you need never have any further involvement with anyone about the case.
"Crimestoppers can't identify who you are and will never ever ask or take any personal details from you.
"So, this really does give someone a chance to do the right thing and help ease our years of pain. We can then see Lee finally laid to rest," Mr Boxall added.
Lee has been described as caring, good mannered, trustworthy and sensitive and was an avid football fan and, at the time, went to Cheam High School.
His parents, Peter and Christine, have kept his bedroom exactly how it was on the day he went missing.
Despite significant coverage speculating that Lee was making his way to watch Crystal Palace play, there is no evidence to prove this.
Police found out he used to visit an outbuilding at St Dunstan’s Church dubbed 'the Shed', a gathering place for teenagers that was targeted by sexual predators.
"We are here for anyone who feels unable to speak directly to the police," said Crimestoppers' Alexa Loukas.
"As we're independent, we offer a safe and secure option when reporting crime.
"Our charity was formed in the year that Lee was last seen and since then, we have always kept our promise of anonymity to the millions who have trusted us with their crime information," she added.
Anyone with information can contact Crimestoppers on freephone 0800 555 111 or use a secure anonymous online form at www.crimestoppers-uk.org. Nobody will know you contacted the charity. Information passed directly to police will not qualify for the reward - only information passed to Crimestoppers will qualify.