A major search of a wooded area as part of the probe into the murder of Deirdre Jacob is underway because of "unusual activity" around the site on the night she disappeared.
The land in the Taggartstown townland, near Usk Little in Co Kildare has been closed off and is under a search warrant which was obtained by the District Court.
Officers are looking for anything of evidential value like human remains or clothing in relation to the Jacob probe or investigations into other missing women.
Inspector John Fitzgerald, who is overseeing the search, told how the search of around 3.5 acres will take up to three weeks.
The "unusual activity" on the night of July 28, 1998, was reported to investigators some time ago.
The area is 15km from Newbridge in Co Kildare where Deirdre, 18, was last seen earlier that day.
The information was reviewed as part of the probe into her murder and has led to the search commencing on Monday.
Insp Fitzgerald said he could not comment on the specific information.
He added that the Jacob family was "in the foremost of our thoughts and motivating us".
Around 15 members of the Divisional Search Team are involved.
Forensic Archaeologist Dr Niamh McCullough will also help members of the Garda National Technical Bureau, a crime scene manager and an excavator.
The site is near where Jo Jo Dullard was last seen in Moone in 1995.
