The family of a teenager who has been missing for more than 21 years and is presumed dead are appealing for information about what happened to him.

Robert Williams was 15 when he was last seen alive and, despite several police pleas, he has never been found.

The teenager left his home in Resolven, Neath, South Wales, on March 22 2002 and is known to have attended a house party in the nearby village of Aberdulais the following day.

Robert’s mother, Cheryl, said: “I know that Robert is never coming home. I just want his body back so I can bury him. He deserves that.

“I don’t want him out there on his own, and we need closure as a family. Someone out there knows what happened to him.

“As a mother, knowing my child is lying somewhere has destroyed me emotionally and physically. I need to know what happened to him.”

Detectives believe the local community in Aberdulais holds the key to what happened to Robert, who would have turned 37 on September 9.

Detective Inspector Dai Butt said: “All outstanding missing person cases remain open and are revisited periodically in case new evidence comes to light. We remain committed to finding out what happened to Robert.

“I believe that the local community of Aberdulais holds key information that might help us understand what happened to him.

“It is known that Robert attended a house party in Tair Felin, Aberdulais, on Saturday March 23 2002, where other local people were present.

“If you were at the party or have any information regarding Robert’s movements or disappearance, we would really like to speak to you.

“It may seem challenging to recall details from 21 years ago, but, no matter how small or insignificant you think the information you hold is, it could prove vital to our investigation and could help provide Robert’s family with much-needed closure.

“All this time without answers has been agony for them – please, if you hold information, it is not too late after all this time to come forward.”

In 2011 a year-long case review concluded that the teenager is most likely dead, having found no evidence to show he is alive.