KEY POINTS:
It was just a routine traffic inquiry, but it locked up a rapist.
Pop Tanupou E'Moala Aholelei, a hardworking Tongan factory-hand, had driven off from a minor traffic incident in June last year.
Police tracked him down through the registration number and brought the then 33-year-old Aholelei into the Glen Innes station for an interview.
So far, so routine. Aholelei was co-operative - so co-operative, in fact, that he agreed to Constable Todd Martin's request to provide a voluntary DNA sample to join the 70,000-odd others in the national database.
While Aholelei went home to await a court summons for a traffic offence, the DNA he'd left on a swab made its way to the Environmental Science & Research headquarters in Mt Albert.
As Aholelei toiled away at his job in Penrose, the DNA sample would go through the largely robotic process of being turned into a DNA profile.
That profile was then filed in the database which soon went through one of its regular runs against the 17,000 samples from crime scenes.
Four weeks after Aholelei gave the sample there was what police call a "hit" and scientists a "link": his DNA matched that left in an unsolved rape from five years before.
A young woman had been snatched from outside the Factory nightclub on O'Connell St.
She was drunk and her friends bundled her into a taxi, but she got out nearby.
The woman cannot remember what happened next, but a witness recalled seeing a Pacific Islander put a Pakeha woman into a vehicle.
When the woman came to, she was in the Parnell Rose Gardens and she was being raped.
She ran - muddied, bruised and without her underwear and some of her clothing - to a nearby hotel, where a security guard called police.
Despite an exhaustive inquiry that included attempts to find the taxi driver, the rapist was never found.
The woman moved to Australia.
Aholelei, meanwhile, had just had his first child. His wife would have two more.
Weekend Herald inquires have found the Tongan immigrant carried on life as normal in the following years, earning a good reputation in his work as a machinery operator at the Penrose company where he packaged food, and continuing to attend the Tongan Methodist church in Onehunga. He had no history as a sex offender.
Detective Constable Damian Espinosa, who had been assigned to investigate the rape in 2001, said Aholelei was surprised when police picked him up. He initially denied the rape, but faced with the DNA link, pleaded guilty in the Auckland District Court this week.
His lawyer's legal challenge to the DNA test failed. Although his relationship had fallen apart for other reasons, Aholelei had otherwise continued on as normal, working in his job right up until the day before his guilty plea.
Describing Aholelei as an "opportunist stalker", Mr Espinosa politely called his decision to give a voluntary DNA sample "naive".
It was a naive decision that led to Aholelei becoming part of the a DNA success rate believed to be the highest in the world - 55 out of every 100 samples taken at crime scenes are found on the database.
And although Aholelei was not actually arrested for his traffic offence, police privately say it is a good example of the success to be had in adopting a policy like that in Britain where DNA samples can be taken "on arrest" just as fingerprints are.
Some believe moving to such a policy will be a natural progression. Mr Espinosa also sees Aholelei's eventual capture as a natural progression.
"This case sends a clear message to those responsible for unsolved crimes that their time will come."
