Gardaí are renewing their appeal for information on Trevor Deely, on the 21st anniversary of his disappearance.
Trevor, who was 22, was last seen in the Dublin 2 area after attending his Christmas party on December 7th, 2000.
Gardaí say the investigation continues to focus on trying to establish the identity of the man dressed in dark/black clothing pictured in CCTV footage talking to Trevor at a gate on Wilton Terrace at the rear entrance to his work place.
An investigation was launched by gardaí at Harcourt Terrace and Irishtown Garda Stations at the time of Trevor's disappearance, and in May 2016 a review and reinvestigation into the disappearance was launched.
Anyone with information is asked to come forward.