Gardai have upgraded the disappearance of Deirdre Jacob to a murder investigation.
Larry Murphy has emerged as a prime suspect after a person gave a statement to Gardai last month.
Deirdre Jacob (18) went missing on Tuesday the 28th of July 1998 close to her home in Newbridge.
It is understood Murphy is residing in London and would be arrested if he were to set foot in Ireland.
Despite the new revelations there is nowhere near enough evidence yet to issue a European Arrest Warrant for his extradition.
Gardai released CCTV footage on Tuesday taken on the day Deirdre Jacob went missing.
In the footage above Deirdre can be seen between 14.35.25 to 14.35.30, walking on the right hand side of the screen (near shop fronts).
She has a bag over her right shoulder, dark hair, t-shirt, dark trousers and white footwear.