Gardaí investigating the disappearance of Deirdre Jacob have launched a murder inquiry.
The 18-year-old Kildare woman has been missing for 20 years.
Deirdre was last seen on the afternoon of 28th July 1998 near her home at Roseberry in Newbridge.
After a 20-year investigation into her disappearance, gardaí say new information has led to the case being reclassified.
Gardaí in Kildare are leading the investigation, with the support of the Serious Crime Review Team.
— Paul Quinn (@PaulQuinnNews) August 14, 2018
Chief Superintendent Brian Sutton explained: "Deirdre Jacob was 18 years of age when she was last seen on 28th July 1998 as she walked to her home in Newbridge, Co Kildare.
"She was a young woman starting off her life, who had just completed one year at St Mary’s University, Twickenham, London."
He added: "Deirdre had enjoyed her life in London and was looking forward to returning to college that September when her life was taken away on or after the 28th July 1998."
He noted that a 'number of lines of enquiry' are being followed.
"We're desperately appealing for more information"
Speaking to Newstalk Breakfast, Deirdre's father Michael appealed for the public's help - calling on people to come forward with any information, no matter how insignificant it may seem.
He said: "The message we need to get to out this morning is that we're desperately appealing for more information.
"We know there's more information... the gardaí are very positive there's more information."
Anyone with information - particularly anybody who has not come forward yet - is being asked to contact Kildare Garda Station on 045 521222 or the Garda Confidential Line on 1800 666 111.
Gardaí have also released a short CCTV video of Deirde captured shortly before her disappearance.
She can be seen on the right hand side of the image, walking near the shopfronts: