The family of Raonaid Murray has called for her killer to "come out from the shadows and own up to what you have done".
17-year-old Raonaid was killed 20 years ago today.
She was last seen alive at around 11:20pm on Friday 3rd September 1999, making her way home from Dun Laoghaire town centre.
Her body was found at Silchester Crescent in Glenageary at 12:33am on 4th September, less than 500 years from her home.
Gardaí say they're fully committed to the investigation - but note there has been no prime suspect and no motive identified in the case so far.
In a statement on behalf of the family released to mark the 20th anniversary, her father Jim said Raonaid "died on the pavement with no loving, caring person there to help or comfort her".
He said: "Raonaid’s killer is free. That freedom mocks what should have been Raonaid’s life and mocks the horror of her death.
"To her killer we say come out from the shadows and own up to what you have done. Do the right thing and confess your crime."
He notes: "It’s twenty years since Raonaid was murdered but to us her awful death is still vivid in our minds and we feel the pain of her loss everyday. We feel that the memory of that time will still be vivid for others as well.
"The gardaí have assured us of their continuing commitment to bring Raonaid’s killer to justice but they need your help. We are appealing for anyone with information that could be relevant to the inquiry to come forward with it to the gardaí."
He noted there were reports at the time of people in the area, but some of those have never come forward.
The statement adds: "We ask anyone who may have as yet undisclosed information to give that information to the gardaí. Help us find Raonaid’s murderer."
Anyone with information can contact the Garda Incident Room at Dun Laoghaire Garda Station on 01-6665000 / 6665012, the Garda Confidential line at 1800-666-111 or any Garda station.
A reward for any critical information received is also available from Crimestoppers, who can be contacted on freephone 1800-25-00-25.
