Twenty years after a woman was burned alive in her own car while on her way to work, police are looking to overseas DNA databases in a bid to find her killer.
Claire Elizabeth Hills, 30, was found dead in the back of her burned out Mazda Familia in the Mangere Domain in the early hours of April 28, 1998.
She was alive when the car was deliberately set alight and died as a result of the blaze.
Police believe Hills, also known as Lisa, was sexually assaulted and have a DNA sample from her killer.
But in the last 20 years there has been no match with anyone on the New Zealand DNA database.
Detective Superintendent Dave Lynch told the Herald on Sunday that police had searched the Australian database - to no avail.
Now he was looking at what other databases could be accessed around the world.
"The reality is in most homicide cases the victim's known to the killer, so we certainly went through a process of identifying all the males that Claire knew and seeking elimination samples from them," Lynch said.
"We also went back and looked at all the original persons of interest on the file and re-sought samples from them as well.
"We also searched the Australian DNA data bank and at this stage, we're unable to find a match.
"The ESR are making some inquiries for us at the moment as to whether there are any other data banks that we can look at and the process we'd need to undertake to do that."
Lynch said in about 2008 forensic scientists were able to build a DNA profile from the original sample gleaned from the crime scene.
That meant the DNA could be run through the local database to see if it matched any other profiles held.
Before then, the sample could only be tested against other like samples.
"That DNA profile has really been the focus of the investigation certainly since then," said Lynch.
"I think in broad terms we've now DNA-tested around 300 people and at this stage we haven't found a match - and finding a match really is the key to advancing this investigation."
Hills was living on her own in a Herne Bay flat and working at McDonalds at Auckland Airport when she died.
She was on her way to work when she was murdered.
"We believe that Claire woke up at 2.30 in the morning, which was standard routine for her," Lynch said.
"There's no signs whatsoever of any struggle or violence within the house so we're reasonably confident that she got up that morning as per her standard routine.
"She usually started work at around half past three so we can assume that she left her house sometime before 3am.
"All we know is that she didn't arrive at work, and that her car was up at Mangere Mountain at about 5.25am when a witness saw a flash of flame and a person running away."
Lynch said there were three scenarios as to why the killer had not been identified through DNA.
"One is that they haven't come to attention post that crime," he said.
"The second one is they may have died; the other one is that they may have left the country.
"So in my experience it would be unusual for someone to have committed a crime like that and 20 years after, not gone on to commit another crime whereby we would take a DNA sample.
"I think potentially one of the other two is probably more likely - but we just don't know.
"We don't need much, all we need is names - we do have the DNA profile to work with and we are able to give assurance of confidentiality around any information that people are prepared to give us."