A schoolboy who mysteriously disappeared 30 years ago was groomed before he was killed, detectives investigating the case now believe.

Police today told how they this year re-examined the historic case of 16-year-old Kevin Hicks's disappearance, which led them to believe he was murdered.

Detective Inspector John McQuade, who is leading the investigation, said looking at the incident with fresh eyes he recognised signs that the boy was groomed.

A £20,000 reward has been offered to anyone who can help solve the mystery of what happened to Kevin when he left his home in Sissinghurst Road, Addiscombe for the last time.

RELATED: Schoolboy Kevin Hicks who went missing 30 years ago was murdered, police now believe

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His mum and dad never gave up hope of finding their son, appealing for information about Kevin, pictured, until their deaths in 1994 and 2004 respectively

DI McQuade said someone in Croydon will know what happened to the John Ruskin School pupil on the night of March 2, 1986.

Kevin's sister Alexandra Hicks, who took the family's lead on the search for her brother after her parents died, is asking anyone involved to come forward.

She said: “Someone, somewhere knows something. And it’s time to let go of that secret.

“I’ve got 15 years of memories, and I’ve got 30 years of searching. It’s time to let it go and [come forward].”

It was first believed that Kevin left his home on the Sunday night to buy eggs for a school project.

But police now believe the trip to nearby shops, less than a two minute walk from his home, was a ruse and that he met with someone.

He was last seen an hour and a half after he left the house.

DI McQuade said the teenager had been trying to conceal a pair of audio speakers they believe were given to him as a gift by whoever was grooming him.

He said: “We now feel that those speakers were, if you like, an inducement around the grooming aspect of it.

“It’s classic grooming. We didn’t really call it that back then, but there is a definitely element of that to Kevin’s disappearance we think.”

When an appeal was launched in 1996, the Croydon Advertiser received an answer machine message from someone who claimed to know the whereabouts of Kevin’s body.

Police were unable to trace the call, and now urge that the anonymous caller to get in touch with investigators.

At around 8.30pm Kevin told his mum he needed to buy some eggs for his O-level home economics exam the next day.

He left with just £1 and headed off to Sperrings community shop on Lower Addiscombe Road.

He was last seen by someone who knew him at 10pm in Shirley Road, walking in the general direction of his home.

DI McQuade, said: "We believe Kevin must have met someone in that hour-and-a-half and that person attacked him.

“Perhaps the suspect didn't mean to kill him but it is clear Kevin's body must have then been disposed of."

Anyone with information is asked to contact the incident room on 020 8721 4005 or Crimestoppers anonymously on 0800 555 111.