An Garda Síochána are seeking the public's help on the anniversary of the 18-year-old student's disappearance. Deirdre was last seen on Tuesday 28 July 1998 near her home in Roseberry, Newbridge, County Kildare, shortly after 3pm.

In 1998, Deirdre had completed her first year at St Mary's University in Twickenham, London. She enjoyed life in London and planned to return to college that September. She would be 46 years old this year.

On the day she went missing, she walked into Newbridge to obtain a bank draft to send a college friend in London for a rent deposit. CCTV and witness sightings tracked her movements: at 2.14pm she was seen on Main Street; around 2.18pm she was in the AIB bank securing a £100 bank draft before leaving; at 2.26pm she was queuing in Newbridge Post Office; by 2.32pm she was speaking with a friend outside the Post Office on Main Street; and at 2.35pm the final CCTV footage recorded her walking past the PTSB bank on Main Street. She was last seen shortly after 3pm near her family home outside Newbridge. Deirdre is described as 5ft 3in tall, of slim build, with grey/green eyes and dark, chin-length hair. When she disappeared she was wearing a navy V-neck T-shirt with white trim on the collar and sleeves, navy or black straight-leg jeans, and blue Nike runners. She carried a distinctive black satchel-style bag with long shoulder straps and the word CAT in large yellow capital letters on the side; this bag has never been found.

A comprehensive investigation has been ongoing for 28 years, with extensive enquiries to establish her whereabouts and the circumstances of her disappearance. On the 20th anniversary of the case, the missing person inquiry was upgraded to a murder investigation, which remains active and is led by detectives from the Kildare Divisional Serious Crime Office under a Senior Investigating Officer.

An incident room continues to operate at Newbridge Garda Station. Deirdre's parents, Michael and Bernadette, and her wider family are regularly updated through a designated Family Liaison Officer.

Investigators urge anyone with information about Deirdre's murder to come forward and stress that no detail is too small—do not assume Gardaí already know it or that it has limited value.

Information can be provided to the investigation team at Newbridge Garda Station on (045) 440 180, the Garda Confidential Line on 1800 666 111, or to any Garda station.