Interpol, the international police organisation, is to be alerted about a possible sighting in India of Richey Edwards, the missing member of the Manic Street Preacher rock group.
Detectives from Scotland Yard have questioned Viv Morris, a lecturer in media studies at Neath College in South Wales, who believes he saw the missing musician at a market in the holiday region of Goa. They believe Mr Morris is a reliable witness and are taking his report seriously.
Interpol and the Indian police are to be given descriptions and photographs of Mr Edwards, who wrote lyrics and played guitar for the award winning Welsh band before disappearing, aged 28, in February 1995 while being treated for depression.
His passport and credit cards were found in his flat in Cardiff and two weeks later his car was found at Aust service station, next to the M4. Its car park overlooks the Severn Bridge and is a favourite spot for suicides. However, his body has not been found, prompting claims by many of his fans that he may still be alive.
A spokeswoman for the Manic Street Preachers said yesterday: "Everyone is very upset by these reports. We are concerned [about Richey]. There have been a number of sightings and the whole thing upsets a lot of people." She added that the members of the band did not want to comment.
Mr Morris, who said he was "seven-and-a-half out of ten" convinced that the man he saw was the musician, said he now regrets the fuss his claim has caused.
He saw a man with long hair who looked like Mr Edwards last November. A stranger said that he was called "Rich" and had arrived in Goa about 18 months before.
Mr Morris told BBC Radio 4's Today programme he had mentioned the sighting in passing during an interview, and the matter had been "seized on". He was now concerned about the "palaver and distress" caused to Mr Edwards' parents. He added a plea for the man who "has worked so hard to gain this anonymity" to be left alone.
"A major tabloid has offered to fly me out to Goa to pick up the trail. Yes, he should get in touch with his family to let them know he's OK. But leave him alone."
A spokesman from Scotland Yard said: "We questioned Mr Morris on Monday. We are fairly confident this is a serious report. The sighting was made in November last year so where the person it now is hard to say. The indications are that it is a positive lead. Whether the sighting is in Goa or Greenwich will still treat him the same way."
He stressed that Mr Edwards was not wanted for any criminal activity. "He might be marked down as a vulnerable person and we would want to see that he was okay."
The controversy comes a week after his former group won best band and best album in the music industry's Brit awards.
Mr Edwards' parents, who live in Blackwood, Gwent, are said to share his fans' optimism and have clung to hope from sporadic sightings of their son, which have been reported in Germany, New York, Bedfordshire and Worcestershire.