Gardaí have released a photograph of a girl found in a distressed state outside the GPO in central Dublin last month.
Detectives hope the image will help them find out who the girl is after all other attempts to identify her failed.
The teenager was found by a garda on patrol on O'Connell Street on October 10th and has been in the care of the Health Service Executive (HSE) since then.
A major garda investigation was launched into the circumstances surrounding the discovery.
The girl is 5-foot-6 in height, of slim build with long blond hair. When found she was wearing a purple hoodie, dark-coloured jeans and a grey woollen jumper.
This investigation - named Operation Shepard - is using specialist child interviewers.
It is illegal to publish a photograph of a child who is in care. However gardaí applied to the High Court for permission, saying they had exhausted every option and had little hope of finding out who the girl is, or where she comes from.
It is feared the girl may be the victim of sex trafficking. The investigation has involved over 2,000 man hours and over 115 lines of enquiry.
It has sought the assistance of Missing Persons bureau, Interpol, the Domestic Violence and Sexual Assault Unit as well as the Garda National Immigration Bureau.
Anyone with information is asked to contact Store Street garda station on 01-666-8100, the Garda Confidential Line at 1800-666-111 or e-mail storestreetappeal@garda.ie
Garda spokesperson Superintendent David Taylor says that despite an intensive investigation, her identity remains a mystery.
