Dr Peter Coop was in Dunedin for a month-long course when he disappeared. Thirty years later, his family are convinced he's dead, while police continue their search for a man they think wanted to disappear.

Dr Peter Coop was 28 and recently married when he went to Dunedin for a month-long course he never made it to. His family believe he's dead, but police think he wanted to disappear. HAMISH MCNEILLY looks into this mysterious case 30 years on.

On a narrow bush track in a remote part of Australia, two slow-moving 4WDs pass each other. Two occupants in one vehicle immediately recognising the other driver.

They say that man was Dr Peter Coop, who vanished from Dunedin eight years earlier on June 6, 1989.

Supplied Dr Peter Coop vanished from Dunedin in 1989. He was there for a month-long course, but never turned up.

"We were certainly close enough to have that lightbulb recognition," Dr Roger Halliwell, a Gold Coast-based general practitioner, said. "I'm 100 per cent sure he recognised us and we certainly recognised him."

READ MORE:

* Dead or disappeared on purpose? The 30-year mystery of Dr Peter Coop

* Thirty-year mystery: The sightings of Dr Peter Coop

* New Zealand's most enduring missing persons cases

* More than 400 New Zealanders recorded as missing by police

* How was Leo Lipp-Neighbours' car found after seven years missing?

* Human remains found in car

His wife, ophthalmologist Elizabeth Hagen, was driving their Toyota Prado when they came across the distinctive pale yellow Lada Niva 4WD at Emu Creek Park, north of New South Wales, in 1997.

Supplied Dr Elizabeth Hagen says she saw her former student friend, Dr Peter Coop, in a remote part of New South Wales in 1997.

As the vehicles moved to the left to pass each other, the couple spotted their former Auckland Medical School classmate.

"That's Peter Coop," Hagen told the stunned Halliwell, who also recognised the missing man.

"Liz would have been able to reach out and shake his hand quite easily."

Supplied Dr Roger Halliwell is convinced the man he saw camping was Coop.

Have you seen Peter Coop? Email hamish.mcneilly@stuff.co.nz

The man they believe was Coop registered a "brief moment of shock", but turned his head and made a comment to the woman he was travelling with.

Halliwell, after returning to the campsite, went for a walk and later saw the man enjoying time with his partner and two young children.

Supplied The missing person file on Coop remains open 30 years on.

"They were toasting marshmallows, or something like that, over a camp fire."

At 5.30am the next morning Hagen decided she would talk to the man, but found the family's camp site had been vacated.

Halliwell said that was further proof it was likely to be Coop, who was possibly concerned he had been recognised.

The campsite was hours away from major centres and was not the place you would go for a one-night stay, particularly as it was just the start of a long weekend.

The couple had studied alongside Coop for six years and Hagen was attending the same ophthalmology course in Dunedin at the time of his disappearance.

The then 28-year-old Auckland-based doctor was in the southern city for the month-long course, which he failed to show up to.

Coop's family believe he could have gone tramping in the bush and died after an accident. However, police believe he staged his own disappearance, possibly because he was stressed about becoming an eye surgeon, like both his parents.

Days before his disappearance, he travelled with Hagen and another colleague from the airport to Dunedin.

Coop had a massive bag he could barely fit in the car.

Hagen later joined in the search for Coop.

The story of Coop was already old at the time of their sighting, and "there was no particular benefit for us to get involved in outing this bloke".

But if Halliwell ever saw him again he would like to ask him if he was "okay" and would respect his privacy.

"I know there are people who want closure, I know there is an open file with police ... but it is 30 years down the line."

Coop must have gone to significant lengths to fake his disappearance and head to Australia, where he once lived, Halliwell said.

The police file, released to Stuff under the Official Information Act, showed investigating officers believed he may have sourced details of a dead person to obtain a birth certificate – and new identity.

HUNTING THE LADA NIVA

While their sighting was reported in 2010 – 13 years after the event – Dunedin Police checked with their counterparts across the Tasman.

In particular they asked for details of the ownership of yellow Lada Nivas in 1997, but was only supplied with details from Queensland.

There were 13 yellow Lada Nivas in 1997, but no false passports were found to be issued to those owners.

Halliwell confirmed to Stuff the vehicle they saw had NSW licence plates, meaning a possible line of inquiry had not been explored.

Police could not track down the camp register, with the 4WD park changing owners. The new owners did not respond to questions.

Bob Webb, the former head of the Australia Lada Owners Club, could not recall any members with a yellow version of the Russian-made vehicle.

That colour was "most unusual", he said.

That colour combination makes it the strongest lead in tracking down Coop, who while being officially missing has not broken any law.

Others close to the doctor contacted Stuff to say they were not surprised by his disappearance.

A former schoolmate said Coop was an excellent artist and mimic, who often spoke of the Australian Outback.

"I think if he is still alive he will be living in Australia."

A former girlfriend said: "I have no doubt at all that Peter staged his own disappearance and moved to Australia to become an artist."

Coop struggled to realise how his actions could impact on people, she said.

"Wherever he is, and whoever he is with, I hope he is happy."