The family of Manic Street Preachers star Richey Edwards claim to have "vital new evidence" in his disappearance.
The musician disappeared from the Embassy Hotel in central London in February 1995, aged 27, and he was officially presumed dead in 2008 - but Edwards' sister Rachel Elias has revealed that new evidence has now come to light.
Edwards' car was found near the Severn Bridge shortly after his disappearance, and Elias has explained the significance of the new evidence.
She said: "We were told that Richard crossed the bridge at 2:55pm.
"And we have the toll booth receipt that says 2:55. So we were led to believe there was an eight-hour window between his time of departing the hotel to crossing the Bridge on that same day.
"But it's since come to light by tracking down the person who made the [bridge's time recording] machines and making enquiries that that was a 24-hour clock, it always was. So that meant 2:55 was 2:55am."
Elias hopes that the information will help to establish a "new line of enquiry".
She told ITV: "So we were appealing to people to have seen him at certain times that day when actually those times are meaningless now.
"We are hoping that it will establish a new line of enquiry because this is vital information that changes everything and turns it all on its head and needs to be looked at again."
Meanwhile, the band - whose last recorded work with Edwards was 1994's 'The Holy Bible' - recently unveiled their new single 'International Blue'.
Of the track, bassist Nicky Wire explained: "On the single and the whole album, there are a lot of mini tributes to things that make your life feel a little bit better.
"Rather than my internalised misery, I tried to put a sense of optimism into the lyrics by writing about things that we find really inspiring."