The father of missing Trevor Deely says he has "renewed hope" of a breakthrough after learning that vital CCTV footage has been sent to Britain for analysis.
The film captures his son's last known movements before his disappearance in 2000.
Michael and Ann Deely will today attend the fourth national Missing Persons Day at Farmleigh House in the Phoenix Park.
Tomorrow, they will be marking the 16th anniversary of 22-year-old Trevor's disappearance with a prayer Mass near their Co Kildare home.
The couple, who have three other children and nine grandchildren, said the anniversary will be more bearable this year after the recent commitment of the Serious Crime Review Team to investigate the high-profile case again.
Crucially, gardai have sent the last-known footage of Trevor - captured on CCTV early on December 8, 2000 - to specialists in the UK for a detailed forensic examination.
Mr Deely (74), who lives in Naas, said he is being kept up to speed on any progress made by a family liaison officer who is part of the Pearse Street Garda Station team. "I've been calling for more resources to be given to the gardai for years to help them solve Trevor's case and the cases of all missing persons," he said.
"I'm delighted that Trevor's case is being looked into again. There's a team of five or six gardai that have been appointed to reinvestigate Trevor's case and I met them a couple of weeks ago.
"There's no body or no scene for them to go on, so they're prioritising the CCTV footage of him which has been taken to the UK where they have more advanced methods of examining it than we do here in Ireland.
"I'm very pleased that there will be some fresh eyes looking into this, and it has certainly given me and my family a big boost.
"I don't want to raise my hopes too much at this stage, but at the same time I feel far more hopeful than I have in years."
As one of Ireland's most high-profile missing persons cases, the image of Trevor and the key facts in his dis- appearance are well-known.
The last-known image of him - and the one that is currently being re-examined in the UK - is of him walking down Hadd- ington Road towards his flat in Ballsbridge at 4.14am.
The IT worker had previously returned to his office where he had picked up an umbrella after a night out at Buck Whaley's nightclub on Lower Leeson Street.
He phoned his best friend and left a message, saying he had had a great night and that he would talk to him later.
He has not been seen or heard from since.
His father said: "It's still our belief that Trevor is alive and I'll carry on believing that until it is proved otherwise."