Updated at 16.05
Gardaí are searching a wooded area in Chapelizod in South Dublin as part of the investigation into the disappearance of Trevor Deely.
Mr Deely - originally from Co Kildare - went missing 17 years ago, and it is hoped the search will lead to a breakthrough in the case.
The then 22-year-old went missing after attending his work Christmas party on Friday December 8th 2000.
He was last seen on CCTV footage crossing Baggot Street Bridge and heading towards Haddington Road in Dublin city centre.
Gardaí launched a complete review of the investigation last year.
In April, a fresh appeal into his disappearance was issued after enhanced CCTV footage showed him talking to a man who detectives believe was 'acting suspiciously'.
The file on Trevor has never been closed, and there have been a number of appeals for information over the year.
However, he has never been found.
Gardaí say the search is being carried out after new information, and will attempt to uncover evidence related to the case.
The search - said to be the most significant since Trevor's disappearance - on the three-acre site will last for a number of weeks.
Detectives say they still have not identified the man in the CCTV footage.
The search is, however, said to be unrelated to the footage.
Detective Inspector Paul Costello explained that the search got underway this morning, and the area has been sealed off.
They say they are searching for 'evidence' in relation to Trevor's disappearance and say it's a 'deeply upsetting' time for the family.
— Stephanie Grogan (@StephGrogan3) August 12, 2017