A fresh appeal for information has been issued by gardaí as part of the investigation into the murder of Paul 'Frank' Byrne almost 15 years ago.
Mr Byrne's remains were discovered in a wooded area by a forestry worker near Blessington, Co Wicklow, on 29 July 2010.
The 20-year-old was last seen a year earlier on 15 July 2009 at Kilmartin Green in Tallaght, Dublin.
It was reported that he left the estate in a 2000 registered wine-coloured Mitsubishi Carisma accompanied by other males.
Gardaí said this was the last sighting of Mr Byrne. He was reported missing by his mother at Tallaght Garda Station the following day.
To date, five people have been arrested in connection with the investigation, however, no one has ever been brought to justice.
"Paul’s family are anxious for the investigation to progress to bring them closure," a garda spokesperson said.
Gardaí are appealing to anyone who may have information since 2009, or who may have come into possession of information in the intervening years, to come forward.
They are "urging individuals, who 16 years on may want to come forward to do so, especially if relationships or associations have changed over the years".
"With the passage of time, people may now feel more comfortable sharing information with gardaí," they added.
Gardaí say they will "treat anyone assisting the investigation in a sensitive manner".
Speaking on RTÉ's News at One, Detective Inspector Seamus Ryan said he was of the belief that there are people out there who know what happened to Mr Byrne.
"There are definitely people out there who would have knowledge of what occurred 16 years on. We are encouraging any individuals who may want to come forward at this time, especially if relations have changed, associations may have differed over the years.
"People may have previously been hesitant or fearful to come forward, but now we are encouraging them to do so at this time. We would obviously treat any information with the strictest of confidentiality."
Mr Ryan said that gardaí had an idea of who may be able to assist them with their investigation.
"Five people have been arrested as part of this investigation and files have been submitted to the DPP, but just haven't met the threshold for a criminal prosecution," he said.
"There are individuals out there who, I believe, have knowledge of what occurred. No matter how small they feel that piece of information may be, it could be that piece of the puzzle that will help us to progress matters with this."
Mr Ryan said that Mr Byrne’s family were anxious to get answers.
"He was a very young man, just setting out on the road to life really. He had everything to live for, was very close to his family, his friends, and much loved by all, and was tragically cut down in his youth.
"It’s very hard for the family to come to terms with after all this time. That's why we're anxious to assist the family and reach out to the public to make the appeal at this time," he added.
Anyone with information can contact gardaí in Blessington at 045 865 202, the Garda Confidential Line on 1800 666 111, or any garda station.
