Gardaí have upgraded their investigation into the disappearance 20 years ago of teenager Deirdre Jacob to a murder investigation.

The Irish Times has also learned gardaí investigating the murder of the 18-year-old have identified a chief suspect.

This suspect is from Leinster and has spent time in prison for violent crime against women.

The investigation into the teenager’s disappearance was upgraded to a murder investigation based on information received recently during a review of the case.

She disappeared on Tuesday, July 28th, 1998, as she was walking from Newbridge, Co Kildare, to her home about 1.5km away.

She had gone to get a bank draft to pay for student accommodation in London where she was studying to become a primary-school teacher.

A missing person poster for Deirdre Jacob issued by the gardaí in 2008. File photogrraph: Garda/PA Wire

She was 18 at the time of her disappearance and no trace of her has ever been found.

New information

In a statement on Tuesday gardaí said: “As a result of new information being received, An Garda Síochána have re-classified the Deirdre Jacob investigation from a missing person investigation to a murder investigation.”

The teenager was last seen on July 28th, 1998 at Roseberry, Newbridge, at about 3pm.

At the time she was living at home for the summer having finished her first year in St Mary’s University, in Twickenham, London.

The missing person case was reclassified as a murder investigation following an intensive review by the Garda cold case unit and local gardaí in Kildare, over the last twelve months.

The murder inquiry is being conducted by gardaí in Kildare alongside the cold case unit.

A Garda spokesman said the “team are following a number of lines of enquiry and progress is being made on the investigation”.

Speaking on Tuesday morning at Naas Garda station chief superintendent Brian Sutton appealed for anyone with information regarding the case to contact gardaí in Kildare, or the confidential hotline.

The Garda investigation team can be contacted at Kildare Garda Station, 045 521222 or the Garda Confidential Line 1800 666 111.

“Deirdre Jacob was 18-years-of-age when she was last seen on July 28th, 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.

“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 July 28th, 1998,” chief supt Sutton said.

Parents of Deirdre Jacob, Michael and Bernadette Jacob, at Naas Garda station, Co Kildare during an appeal to the public marking the 20th Anniversary Deirdre’s disappearance this year. Photograph: Gareth Chaney/Collins

Difficult time for family

Her father Michael Jacob said his family had been informed of the development “as a result of useful information coming in since our last appeal”. He said even though the family were aware this was about to happen “nevertheless when we were listening to it over the airwaves and on the TV this morning it still came as a shock, just hearing those sort of words that Deirdre was murdered. It’s a real heart wrenching situation”.

He said they always held out hope. “You always look for a glimmer of hope ...but now with the investigation going in this direction obviously it’s a difficult time,” he told RTÉ’s News at One.

He hoped the coverage the story is now getting will encourage anyone with information to come forward. “Now is a good time to tell ... so the next few vital steps can be made”.

Hoax caller

Mr Jacob and his wife Bernie have issued previous appeals for information several times over the last two decades.

They told The Irish Times in an interview a number of years ago that one of the most difficult periods of the last 20 years was when a hoax caller contacted gardaí about 10 days after her disappearance.

The last known image from CCTV in Newbridge of missing Deirdre Jacob. Photograph: Colin Keegan/ Collins Dublin

Based in Co Fermanagh, the man first called the Leinster Leader newspaper, in Kildare, and then several Garda stations. He said he gave a lift to a girl from Clane village, in Co Kildare, to Carrickmacross, in Co Monaghan.

Following the calls the search in Co Kildare was stopped and the operation diverted to Monaghan and Fermanagh. The family travelled north based on the information from the hoaxer.

At the request of the family the tape of his calls was released and played on RTÉ. “Within half an hour they had so many calls they knew who he was,” said Michael.

“They said he had had a tragedy in his own family, and this is why he had done this,” said Bernie Jacob. “I find it impossible to reconcile that, having gone through a tragedy himself, he would impose one on us.”

On the day her daughter disappeared, Bernie Jacob returned to find the front door locked, which set off alarm bells as it meant her daughter had not returned home.

A large scale search by gardaí, local volunteers, and Civil Defence teams in the weeks after her disappearance failed to turn up any clues in the case.

The student’s disappearance is one of six high profile cases involving young women who went missing in the Leinster area during the 1990s.

Operation Trace was the name given to the Garda investigation set up to examine if there were any links between the cases, which included Fiona Sinnott, Josephine Dullard, Ciara Breen, Fiona Pender and Annie McCarrick.

No links between any of the cases were ever found. And though all of the cases remain unsolved and none of the women’s remains were ever found, gardaí believe they were all murdered.

In some of the cases gardaí have had clear suspects for years. For example, Fiona Pender, Fiona Sinnott and Ciara Breen are believed to have been killed by men known to them.