A man has been arrested for questioning in connection with the disappearance presumed murder of 17-year-old Ciara Breen in 1997.
The suspect's detention is the first arrest in the 18 years since Ms Breen was last seen alive at her home in Dundalk, Co Louth.
The arrested man is from Dundalk and is in his 50s. He was known to Ms Breen but is not related to her.
Gardaí have in the past regarded him as a suspect in the case and believe he was in Ms Breen’s company after she was last seen alive by her mother at their Dundalk home.
But it was only when new information came to light relating to sightings of Ms Breen that gardaí believed they had sufficient grounds to arrest the suspect.
He has been detained under Section 4 of the Criminal Justice Act and is being question at Drogheda garda station. He can be interviewed for up to 24 hours without charge.
Ms Breen’s case was part of Operation Trace which was established by the Garda in 1998 to determine if there were links between the disappearances of a number of women in the Leinster area.
Other cases examined include the disappearances of Deirdre Jacob, Annie McCarrick, Jo Jo Dullard, Fiona Sinnott, Fiona Pender and Eva Brennan.
No connection was found and none of the women’s remains have been discovered nor has anybody been charged with any crime in relation to their disappearances presumed murders.
Ms Breen was last seen in her Dundalk home, on Bachelor’s Walk, by her mother Bernadette on the night of February 12th into the early hours of the 13th in 1997.
She explained at the time they had both gone to bed just after midnight.
“I got up at 2am to go to the toilet and I looked in (her bedroom) and was she wasn’t there. She didn’t take any money or clothes with her. It is as if she went to meet somebody and did not get back.”
Bernadette Breen believes Ciara had left a window on the latch so she could climb back in. She waited for her to return but she never saw Ciara again.
Last July a new witness contacted gardaí and relayed information about a credible sighting of Ms Breen after her mother had last seen her alive.
Last November another witness came forward with another sighting dating back to the time Ciara disappeared.
The Garda investigation also received two anonymous letters about the case late last year; one in November and one in December.
The case featured in RTÉ's Crimecall programme in December, with gardaí urging the authors of the letters to come forward.
Bernadette Breen also made an emotional appeal on the programme.
“I had just one little girl; my heart, my soul, my world. And just like that she was gone,” she said.
“She was not streetwise and she paid the price. And if anything comes out of this I would like it to be for whoever has the information we need for Ciara to give it.
“Please, please, don’t let her lie out there on her own any more, let her come home.”
Det Insp Pat Marrey told the same programme the investigation team regarded the sightings and letters over the preceding six months as significant.
“A lot of the people we canvassed and spoken to back in 1997 were people 17 and 18 years of age,” he said of the original investigation.
“Those people are now in their mid-30s, married with families and children. I would ask those people who have information to contact us, no matter how miniscule.
“They have nothing to fear, absolutely not. We wish to put an end to Bernadette’s suffering.”
