Gardaí have issued a renewed appeal for information ahead of the 25th anniversary of the murder of 17-year-old Raonaid Murray in Dublin.
Ms Murray's body was found close to her home at Silchester Crescent in Glenageary in the early hours of 4 September 1999.
Gardaí said they have taken more than 4,500 witness statements since, but no motive has been identified for her murder.
Ms Murray was last seen alive at around 11.20pm on Friday 3 September 1999 when she made her way home from Dún Laoghaire town centre.
She had been working at a clothes shop, then known as Sally West, in Dún Laoghaire Shopping Centre.
After leaving the shop at around 9pm that night, she went to Scott's Public House with a friend.
She had arranged to go to a nightclub later that night and left the pub at around 11.20pm to go home and change before heading to the nightclub.
However, she never made it home. Her body was found less than 500 yards from her home at 12.33am.
Gardaí said that with the passage of time someone may now be in a position to provide information that they could not at the time, or someone who did provide information could now be in a position to provide further information.
Gardaí said if anyone has information which could assist in identifying a motive for the murder of Raonaid or if anyone has any doubts about the truth of an alibi already provided, they are appealing for assistance.
Detective Superintendent Brian O'Keeffe added: "An Garda Síochána and Raonaid's family would urge anyone with any information to please come forward.
"By not coming forward with that information you may be unknowingly shielding a killer."
Gardaí said that solving the murder is of the utmost priority and that any interactions will be treated with confidentiality, compassion and sensitivity.
Anyone with information is asked to contact the incident room at Dún Laoghaire Garda Station on 01 666 5000 or 01 666 5012, or the Garda Confidential Line 1800 666 111.
