Ciara: An only daughter who paid the price for not being streetwise
Ciara Breen was last seen alive at her home at Bachelor's Walk in Dundalk in the early hours of February 13, 1997.
The previous evening the 17-year-old trainee hairdresser, who was an only child, had tea with her mother Bernadette in a local café around 6.45pm.
Later they watched TV before going to bed around 12.25am.
Bernadette discovered her daughter was missing when she went to check on her at 1.50am.
However, her mother decided to wait up for Ciara's return because it wasn't unusual for her to slip out in the middle of the night.
Investigators, who were alerted the next morning, believe that the teenager was murdered when she went to meet a man who remains the key suspect.
This latest development in the enquiry came after two witnesses came forward with information to gardaí in July and November last year.
It is understood that they gave valuable sightings of the missing teen on the night she vanished which had not come to light before.
Detectives also received two anonymous letters in November and December which they described as "very significant" and which pointed to the identities of Ciara's alleged killer and an accomplice.
On the Crimecall programme in December Det Insp Pat Marry said investigators believed that Ciara came to serious harm on the night she disappeared.
Ciara's mother Bernadette also made a heartfelt plea: "I had one, just one little girl; my heart, my soul, my world, and just like that she was gone.
"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."