John Beckenridge's car was pulled from the sea near Curio Bay in May 2015 after lying beneath an 88m cliff for nearly two months. Beckenridge has been missing along with his stepson, Mike Zhao-Beckenridge, 11, since March 13, 2015.

It's been almost a year since 12-year-old Mike Zhao-Beckenridge hung out with his friends and a year since he saw his mother.

It's been almost a year since his life was either cruelly ended or changed forever.

The Southland boy's been missing, along with his step-father John Robert Beckenridge, since March 13, 2015.

SUPPLIED Mike Zhao-Beckenridge and his stepfather John Robert Beckenridge.

This is a case riddled with questions: If the two are dead why haven't their bodies been found? If they're alive, why haven't there been any sightings?

READ MORE:

* No bodies recovered in Beckenridge car

* Beckenridge: Family hopeful missing boy is alive

* Hunt for Mike Zhao-Beckenridge remains open

* Missing boy Mike Zhao-Beckenridge wanted life with stepdad

* Search for Mike Zhao-Beckenridge: Police believe missing car located

SUPPLIED Some believe the pair are dead but some experts and Mike's family think they could still be alive.

Beckenridge's background has fuelled the speculation. The Swedish-born 65-year-old has multiple passports and at least four known aliases.

SUPPLIED Beckenridge's international connections, multiple passports and string of aliases have fuelled speculation about the case.

He worked as a helicopter pilot in Papua New Guinea and Afghanistan and has connections around the world.

A year has passed since Mike was ripped from his life in Southland but as the anniversary of his disappearance draws near, his family clings to hope. They believe he's still alive, and they're not alone.

A number of experts including a private investigator, who has examined a number of similar cases including child abduction investigations, insist the duo could be out there in hiding.

GOOGLE MAPS The pair were last seen near the Catlins in Southland before Beckenridge's car was found in the sea beneath an 88m cliff near Curio Bay.

But is it really possible they are still alive, hiding either here or overseas?

THEY COULD STILL BE ALIVE

A source close to the family said Mike's mother now believed her son was alive.

JOHN HAWKINS/stuff.co.nz Inspector Kelvin Lloyd, Area Commander Southland, talks about the next step in the search for missing Invercargill boy Mike Zhao-Beckenridge.

The source said he had always thought the pair were alive but it had taken a while for Fiona (Fengjuan) Lu to come to the same conclusion about her son.

Mike's disappearance had deeply affected Lu, he said.

"She's just started to be a person again."

NICOLE JOHNSTONE/FAIRFAX NZ It took almost two months before police were able to recover Beckenridge's vehicle from the ocean.

The source said the family tried to avoid the discussing the subject in fear of upsetting Lu and he was worried the anniversary of Mike's disappearance would cause her renewed distress.

Meanwhile, a private investigator and criminologist also believe Mike and his stepdad are alive.

Then initial theory of murder-suicide committed by a scorned father, separated from his stepson, lost its legs after Beckenridge's car was found in the Southland sea with no traces of the bodies.

ROBYN EDIE/FAIRFAX NZ Some friends and neighbours of Beckenridge believe he faked his own death and fled overseas with his stepson.

Paragon Investigations managing director Ron McQuilter said his best guess was the pair was in hiding in a remote part of New Zealand.

It was possible one body could have disappeared in the rough seas at the bottom of the country after the car plunged off the 88-metre cliff, McQuilter said.

But if Mike and his stepfather were in the car at the time police would have found some trace of them by now, which helped substantiate the possibility they were still alive, he said.

stuff.co.nz Scene of the search near Curio Bay for Mike Zhao-Beckenridge and his father.

Some friends and neighbours of Beckenridge said they believed he faked his death and fled overseas, possibly to Papua New Guinea or Australia.

McQuilter said the theory Beckenridge could have flown a helicopter to Australia was widely debunked but it was entirely possible for the pair to disappear in New Zealand.

There were communities in the South Island and the Coromandel where people went when they wanted to get off the grid, he said.

ROBYN EDIE/FAIRFAX NZ Mike's bag was also found during the police search last year.

"If you put your mind to it, you can definitely disappear."

Beckenridge and his son would have to lead a "very meagre existence", he said.

They had probably changed their names and hair colour and were staying in a place where people didn't ask questions.

JOHN HAWKINS/FAIRFAX NZ Divers attached floats to the salvage car wreck in Blue Cod Bay near Curio Bay during the recovery.

McQuilter said he was confident time would out them eventually.

University of Canterbury criminologist Greg Newbold also believes Mike and his stepfather are alive but thinks it's more likely the pair are overseas.

Newbold said the police focus on retrieving the car at the bottom of the Southland cliff presented a "window of opportunity" where Beckenridge could have shot off.

1 of 7 Robyn Edie Police national diver squad members from Wellington work off the boat Awesome, which is taking the divers to an area off cliffs near Southland's Curio Bay. 2 of 7 Robyn Edie Police check a cliff top on private land during the search for missing Invercargill boy Mike Zhao-Beckenridge, 11, and his step-father John Beckenridge. 3 of 7 Robyn Edie Police national diver squad members from Wellington, Sergeant Nigel Bullock, left, and Officer in Charge Senior Sergent Bruce Adams, are picked up in Porpoise Bay by an inflatable to go out to the boat Awesome, which is taking the divers to an area off the cliffs. 4 of 7 ROBYN EDIE/FAIRFAX NZ Search and Rescue volunteers Rodney McCraw, of Owaka, left, and team leader Lianne Latta, of the Catlins. 5 of 7 ROBYN EDIE The view from the lookout at the Curio Bay camping ground, looking towards the area the police are working in their search for Mike Zhao-Beckenridge. 6 of 7 Robyn Edie Police head onto a cliff top on private land near Curio Bay in their search for missing Invercargill school boy Mike Zhao-Beckenridge, 11, and his step-father John Beckenridge, 64. 7 of 7 Robyn Edie Craig Leith, of Tokanui, left, and team leader Lianne Latta, of the Catlins, search along the coastline about 2 kilometres from the Curio Bay camping ground.

The Swedish-born helicopter pilot had connections overseas and a number of aliases to help him disappear.

"It's definitely possible to live overseas without being found, you've just got to be clever," he said.

"I think at some stage that young fella will turn up and write a book."

Police have declined requests to be interviewed but provided written responses to questions about the investigation, saying that it is still being treated as a missing persons case.

Senior Sergeant Dave Kennelly said so far, all sightings reported to police have been followed up and subsequent inquires have resulted in no confirmed sightings of the pair, the border alerts have not been triggered and no new leads have come to light.

THE DISAPPEARANCE

SUPPLIED Police were able to confirm the car found in the sea was Beckenridge's dark-blue Volkswagen.

Mike Zhao-Beckenridge was on his lunch break at James Hargest Junior Campus in Invercargill when John Robert Beckenridge collected his step-son on March 13.

Mike's mother Fiona (Fengjuan) Lu had recently broken it off with Beckenridge - a Swedish-born helicopter pilot who used a string of aliases.

Beckenridge and Lu married in 2007 but separated in April 2013.

SOUTHL:ND POLICE/SUPPLIED When the car was finally recovered police were unable to say whether Mike and his stepdad were inside when it plunged over the cliff.

Beckenridge's friend of 40 years, Swedish airline pilot Roger Henricson, said Mike was desperate to return to his stepdad and police say they believe Mike went with his father willingly when he met him at school.

Shortly after Mike was reported missing, police activated border alerts for the pair, including for anyone travelling under Beckenridge's known aliases of John Locke, John Lundh, Knut Goran Roland Lundh, and John Bradford.

The Interpol alerts have not been triggered but there was a report of a man entering Papua New Guinea under one of Beckenridge's aliases - John Locke - in February 2015. There are no records of this man leaving the country.

JOHN HAWKINS/FAIRFAX NZ A close up of the car linked to missing Invercargill boy Mike Zhao-Beckenridge, found near Curio Bay.

Police have followed up on the alert.

Three days after the pair's disappearance, on March 16, a farmer noticed Mike and Beckenridge in a remote bush area near Slope Point in the Catlins and reported the sighting to police. This remains the only confirmed sighting of the pair since they disappeared, despite others reported until April 2015.

Police searched the surrounding area until Sunday, March 22, when car parts and a backpack were found washed up on a beach in Curio Bay.

NICOLE JOHNSTONE/FAIRFAX NZ A buoy (lower centre in photo) in the water marks the spot where an oil slick was discovered in a bay near Curio Bay when police searched for Mike Zhao-Beckenridge.

During the next several days, dozens of search and rescue volunteers scoured kilometres of coastline, finding more car parts.

Eventually police found the spot where Beckenridge's dark-blue Volkswagen Touareg could have been driven over a cliff.

After multiple thwarted attempts by the police national dive squad to enter the water, on March 26, an underwater camera was used to confirm a car wreck rested on the ocean floor beneath an 88-metre cliff near Curio Bay.

ROBYN EDIE/FAIRFAX NZ The search was hindered by rough seas, bringing frustration to the family and the search team.

Police confirmed the parts and wreck were Beckenridge's car, and the backpack found washed up on the beach was Mike's - the evidence pointed to a murder-suicide.

But when police finally pulled the car from the water on May 6 no bodies were found in the car and police were unable to say whether the pair had been in the vehicle when it flew over the cliff.

The police investigation remains open and Coroner Marcus Elliott cannot launch an inquiry until he gets the go-ahead from police.

Robyn Edie Some say the rough waters could have lay claim to the bodies but a private investigator says if the pair was in the car when it went over the edge some trace of the bodies would have been found by now.

PROPERTY DISPUTE

There is also another strand.

Following Mike and Beckenridge's disappearance, Lu filed legal action to find if her son is a beneficiary of Beckenridge's Queenstown house.

1 of 5 JOHN HAWKINS/FAIRFAX NZ A close up of the car linked to missing Invercargill boy Mike Zhao-Beckenridge, found near Curio Bay. 2 of 5 SUPPLIED Mike Zhao-Beckenridge, 11, has been missing since March 13. 3 of 5 JOHN HAWKINS/FAIRFAX NZ Divers enter the water to attach a rope to the car wreck in Blue Cod Bay. 4 of 5 JOHN HAWKINS/FAIRFAX NZ Salvage boat Awesome arrives at Curio Bay. 5 of 5 JOHN HAWKINS/?FAIRFAX NZ A salvage helicopter with rope attached to car wreck in Blue Cod Bay near Curio Bay.

The Lake Hayes Estate property where Mike lived with his father before moving in with his mother in Invercargill has a rateable value of $700,000.

Ownership of the house was transferred from Beckenridge's name into a trust, of which Beckenridge and his friend Henricson are beneficiaries.

It is understood the house was transferred into the Ozprey Trust so Mike could also be made a beneficiary.

GOOGLE MAPS Beckenridge's Queenstown home has lay empty since the pair disappeared.

Lu sought a court order to appoint Public Trust as the trustee for the Ozprey Trust, substituting Beckenridge, in order to protect Mike's interests in the house.

Judge Robert ​Osborne ruled to have Public Trust appointed to represent Beckenridge in his capacity as trustee.

But until the coroner provides a ruling on the case, the dispute over who gets the house or proceeds from the sale cannot be settled.

HOW THE MYSTERY UNFOLDED

February 2015

Man enters Papua New Guinea using one of John Beckenridge's aliases - John Locke. No reports of that man leaving the country.

March 13

John Beckenridge, 64, takes stepson Mike Zhao-Beckenridge, 11, from Invercargill's James Hargest Junior Campus at lunchtime.

March 16

Southland farmer reports sighting of Mike and Beckenridge near Slope Point in the Catlins. This remains the only confirmed sighting since the disappearance.

March 18

Police seek help to find the pair who are thought to be travelling in a dark-blue Volkswagen Touareg.

March 22

Police carry out search operation in the Tokanui and Haldane areas until car parts and a backpack are found washed up on a beach in Curio Bay.

March 23

Police divers join search at Blue Cod Bay, but conditions hinder efforts.

March 24

Police find vehicle wreckage in Blue Cod Bay.

March 25

Wreckage confirmed as Volkswagen Touareg.

March 30

Police divers confirm car is Beckenridge's dark-blue Touareg.

April 8

Police say evidence points to the pair being inside the car when it plunged off the 88-metre cliff.

May 6

Divers and helicopter recover car, which is taken by boat to Bluff

May 18

Police forensic examinations find no signs of human remains in car.

April 2015

Last sightings reported to police.