Police are referring the disappearance of an University of Auckland student to the Coroner after extensive inquiries did not bring the answers his bereft family were looking for.
It comes shortly after the missing 22-year-old's family posted a reward of $200,000 for information.
The sum is thought to be the largest offered in the country for information on a potential crime - nearly double what police announced last month in their bid to flush out a cold case killer.
Guoquan Wu, also known as Laurence Wu, has been missing for more than 12 weeks.
Wu, was last seen on March 10 on Sainsbury Rd, in the suburb of St Lukes.
His vehicle - a Hyundai Santa Fe - was found at Piha Beach car park two days later.
Sergeant Tania Kingi said police understood how "devastating his disappearance has been for his family" and that their hearts went out to them.
"The police staff involved in this investigation wanted nothing more than to be able to provide the answers that the family so desperately seeks at this time, and it is unfortunate that we have not been able to achieve this, despite our best efforts."
Since his disappearance and the discovery of his vehicle in Piha, police have carried out multiple land searches in the surrounding area, she said.
"We have also undertaken several aerial sweeps of the region, while ground searches have also been carried out across the wider Waitakere coastal area.
"Sadly, none of these searches has uncovered any trace of Laurence."
Kingi said police had issued multiple public appeals for information and as a result had spoken to a number of people in the Piha area, and those who were last in contact with Wu.
CCTV footage was extensively reviewed, including footage of when he was last seen on Sainsbury Rd.
Police also examined the contents of his vehicle, including his laptop, as part of their investigation.
"After completing all lines of inquiry, there is no evidence to suggest foul play in connection with his disappearance.
"Police are not treating his disappearance as suspicious and the matter is being referred to the Coroner.
"We have been working closely with his family and our sympathies are with them at this difficult time."
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