A ban has been imposed on the flying of drones over the site in Dublin where gardaí are searching for the remains of Trevor Deely.
The Irish Aviation Authority has announced a "Temporary Restricted Area" over the search zone in Chapelizod Demesne.
It follows a request from the Justice Minister Charlie Flanagan on security-related grounds.
It means all unlicensed aircraft - including model planes and drones - must keep away from the area.
Gardaí are continuing their search after a tip-off that the remains of the 22-year-old could be buried there.
Trevor was last seen in Dublin city centre after his Christmas party almost 17 years ago.