Detectives hunting the killer of a student backpacker 20 years ago have made a breakthrough in their investigation.
A DNA sample taken from the forest in the North where Inga Maria Hauser's body was found in 1988 has shown similarities with the profiles of a number of women stored on the UK genetic national database.
Police now want to speak to these women in an effort to eliminate male relatives from their enquiries.
Detective Superintendent Raymond Murray from the Police Service of Northern Ireland said: "DNA science is developing all the time.
"We can infer from the way that DNA characteristics are inherited that there is a possibility, and no more than that, that in this small female group there is a male relative's DNA profile which could match the DNA profile from the crime scene."
Inga Maria, 18, was found dead in a remote part of Ballypatrick Forest on the outskirts of Ballycastle, North Antrim on April 20, 1988.
The German student had been subjected to a vicious and ruthless assault.
She had travelled to the North on April 6, arriving in Larne on a ferry from Scotland. Police believe she died shortly after.
Forensic scientists found a DNA sample from a male at the crime scene. However, despite extensive investigations, he has never been identified.
While the DNA is not on the national data base of offenders, police have now discovered other samples that share similar characteristics with the profile.
This included samples from men and women, however, experts have now ruled out a link with the male profiles after further genetic analysis.
Police are now focusing their enquiries on the samples of the females, who live across the UK.
"It is important that we locate male relatives of this limited number of women so that a sample can be taken from them and they can be eliminated from this investigation," said Mr Murray.
Members of the local community have already co-operated extensively in a voluntary DNA screening process.
Mr Murray said: "I believe this is a proportionate and appropriate next step in this investigation to locate Inga Maria's killer. The science is telling us there might be a link between a male DNA profile from the crime scene and a small number of women across the UK who are on the DNA database.
"It is our duty to follow this line of inquiry for two reasons: firstly, to eliminate these individuals from the investigation; secondly and, most importantly, to ensure that we have done everything possible to apprehend the killer of a young woman whose life was taken from her in the most cruel circumstances."
Police plan to conduct these new inquiries, with the assistance and co-operation of the women concerned, in the coming weeks.