The missing persons sign that hung for nearly a year in the window of the emergency shelter has been taken down and police have also stopped handing out flyers to bushwalkers and skiers as they enter the national park in the desperate hope than one of them, somewhere, may stumble upon an overlooked clue to one of the biggest mysteries ever played out in the high country.

It is almost a year to the day that Canadian hiker Prabhdeep Srawn parked his rented Jucy camper van in the village below the car park, stashed his laptop under the car seat, grabbed the $45 jacket he had bought in Jindabyne on his way through and set off on the popular Main Range Walk towards Australia’s highest peaks. He was never seen again.

By the weekend of May 18-19 a staff member at the resort had noticed the abandoned vehicle with a 24-hour park entry pass on its windscreen, which had not moved since its arrival the previous Monday, and alerted police.

What followed was a massive four-week search involving up to 40 people at a time, three helicopters, some of which were equiped with infra-red sensors, police dog squads, survivalist experts and an international contingent of volunteer and professional alpine rescue personnel.

As the weather deteriorated, dumping snow and whiting out the peaks, search crews scoured the mountains on foot and from the air, at times in foul weather, with their patterns recorded on GPS receivers and plotted into a colour-coded map showing who had been where, allowing those in the Jindabyne coordination centre to identify any uncovered ground.

Not since the disappearance of four snowboarders in 1999 in a nearby area of Kosciuszko National Park had a search of such magnitude been undertaken, and never with the same level of technology and high-tech equipment. But despite all the sensors, experts, data analysis and subsequent repeated searches, no trace of the 25-year-old Bond University law student has been found.

After the failure of the initial search, there had been high hopes that his remains or some clue would be revealed when the snow melted, as was the case with the missing snowboarders whose bodies were discovered in a snow cave in the spring. Two major searches for Srawn were conducted during November and February, while smaller individual trips to check remaining areas were also conducted.

But as the winter fronts approach, preparing to cast a thick white cloak over the alps, those hopes of answers to what happened to the young man known to his family as Prabh appear set to once again disappear under the falling snow.

In his upstairs office at the imposing concrete bunker of Queanbeyan Police Station, Superintendent Rod Smith is collating a file on the search for Srawn. Having spent months poring over the evidence, false leads, and reems of data from the multiple state and federal agencies involved in the search, the file will soon be handed to the NSW Coroner, even though no body or any of Srawn’s possessions have been found beyond the camper.

When I ask him if he thinks it unusual that no single item of the missing man’s equipment was found in the grid-like combing of the search area he shakes his head.

“I’ve been up there myself, I’ve seen it and I was blown away by how treacherous it is when the weather comes in. If you fell off one of those rock faces it’s a long way down and underneath it’s very thick scrub. On top of that it’s a massive search area.”

But not everyone in Jindabyne is convinced the story is a simple case of an ill-prepared hiker becoming lost in poor weather.

Mountain guide Bruce Easton has operated his specialist backcountry ski shop in Jindabyne for 25 years. He was involved in supplying equipment and expertise in the search for both the snowboarders in 1999 and Srawn. He does not believe the young man would have gone over the edge of the range into the wild and jagged valleys of the Western Fall Wilderness Area where much of the search was concentrated.

“People don’t understand how rough the terrain is out there [west of the main trail], it’s scary. People who don’t have experience take one look and go the other way, and people who do know what it’s like know better than to go down there.”

During the initial search, rescuers dropped into the area had to be pulled out a short time later by helicopters because they were unable to make any progress through the steep, boulder strewn scrub and cliffs.

“The fact that they didn’t find a single item of clothing, not a backpack, not so much as a scrap of toilet paper out there doesn’t add up. I understand people want resolution, but given how many people go through that area, why didn’t they find anything in summer?”

In the warmer months the 18-kilometre-long lakes walk loop on the main range and side trip to the summit of Mt Kosciuszko is one of the most popular trails in Australia. According to the NSW Parks and Wildlife Service, 8000 to 10,000 people hike the lakes walk or walk to Blue Lake and return each summer.

One of the strongest arguments against the theory that he disappeared deliberately are the pings recorded from Srawn’s mobile phone. As his phone checked in with the surrounding towers, it left a digital breadcrumb trail that police were later able to triangulate to determine his approximate position and time.

“All the information from the phone indicated that he had gone out on the Main Range Trail in an anticlockwise direction from Charlotte Pass and it pretty much finishes around the Mount Townsend area at the time the storm came in,” Superintendent Smith says.

Police also received GoPro video footage of the storm front coming in and reports of footprints in the snow from other hikers in the area. Following the search, Srawn’s family also hired a private detective who concluded that the young army reservist had not staged his disappearance.

Srawn was due to return to Canada a few weeks after his trip to the mountains. One of his closest friends, John Hagg, who had asked Srawn to be a groomsman at his wedding on his return, has another theory about what could have happened to his friend.

“It seems so bizarre to believe some of the suspicions that people have about Prabh trying to disappear himself. You’d think people might get the impression that was his plan, but I got no indication from any of the interactions I had with Prabh that there was anything weird going on.

“I would almost lean towards him being kidnapped or something crazy like that. He went to New Zealand by himself and made a million friends and travelled around with them. He randomly bumped into people and became friends.

“I don’t see it as too far-fetched that he bumped into someone and was hanging out with them and it turned out that they were not a nice person. I don’t want to think about that, but I can’t imagine he straight up disappeared on his own and left everyone in the lurch.”

Jindabyne local and experienced backcountry skier Andrew Barnes has spent years exploring the main range and the area where Srawn is believed to have gone missing.

I contact him to ask him about the terrain, and the likelihood of anyone going into the western falls area by accident while hiking on the main trail when he says something that stops me in my tracks.

“You know, I was skiing the weekend after that guy went missing [but before he was reported as lost] and got whited out down the bottom of Little Austria [a steep area off the main range trail favoured by backcountry skiers]. I could have sworn I heard someone calling out way away. I’ve always wondered if it was him.”

It wasn’t until weeks later that Barnes learned of the man’s disappearance through media reports. Several days after that experience and with the search now underway, three Snowy Hydro staff searching the nearby Opera House hut area also reported hearing calls for help about four to five kilometres from where Barnes had been skiing. Helicopters and extra searchers were sent to the area, but nothing was found.

I mention Barnes’s story to Superintendent Smith, and ask if he thinks it’s related to the separate report from the helicopter crew, and if it’s possible it may have been the missing man.

“We’ve also spoken to people who have a strong affiliation with that area who say that the wind - and this sounds bizarre - but the wind in the trees down there can make a sound like someone yelling out, a kind of howling sound. We’ve had people say to us that they’ve heard before what sounds like someone yelling when in fact it was just the wind through the trees and the branches rubbing together.”

With a forecast of several days of fine weather and emergency equipment packed, I ask Barnes to take me out and show me the area where he thought he heard the voice, and the area police believe Srawn may have taken a wrong turn.

We climb out of the Snowy River towards the ridge above Little Austria and snow drifts and patches of ice obscure small sections of the path. As we stand on the exposed ridge and look over the edge into the Western Fall Wilderness and Victoria beyond, I ask Barnes if it could have been the wind he heard.

“It could have been,” he shrugs. “It was one of those moments where you’re on your own and there’s no one around and you hear something once like someone calling out that makes you stop. I didn’t hear it again.”

As we head back down from the exposed ridge towards Charlotte Pass, we come across a pair of French tourists traipsing through the snow. Neither appears to have weatherproof clothing or substantial packs. With the afternoon starting to get late, we turn them around and implore them not to continue any further before the sun sets.

Days after the search for Srawn began, desperate family members left their southern Ontario home of Brampton in Canada for Australia. As they reached out for help from the local community, offering rewards of up to $100,000 for anyone who found the missing man, Jindabyne ski instructor Shawn Joynt answered the call.

Joynt, herself a Canadian expat, offered her home at no cost to the family for as long as they needed it, and says they arrived with hope and confidence, and left shattered.

The case of the missing man had struck a chord with Joynt, who 20 years earlier had experienced a similar ordeal.

Backpacking through Australia as teenagers with a couple of girlfriends, Cherie Guthrie and Nicole Verge, a loose end saw the trio headed for the mountains where they were taken in by entrepreneur and adventurer Dick Smith and wife Pip.

After months traveling with the Smiths and hiking and camping through some of the wildest areas of Kosciuszko, Joynt returned to Canada only to be met at the airport by her ashen-faced father with the news that one of her friends had drowned in the Snowy River.

Cherie and Nicole had been exploring a section of the river below Guthega Dam when heavy rain set in. As the waters began to rise and flood over the dam, the pair was trapped on a large rock in the raging torrent.

Nicole, the stronger of the two, managed to make it across the water, and headed through the bush searching for help. Hypothermic and delirious, she emerged from the scrub six hours later onto the Guthega road where she was found by searchers. Cherie’s body was not found until a day later, downstream near the Guthega Power station.

Turning around at the airport and heading straight back to Jindabyne, Joynt says it was a confronting and confusing time, where few people were willing to reach out to help. She recognised the same sense of dismay in the Srawn family.

“Australia just doesn’t have the same sense of community that you find in Canada. I found out that this family lived just a few streets away from my father in Bampton, so I knew I had to help.”

When the family called in an 18-member team of rescue experts to assist the Australian authorities, she recalls them arriving full of bravado.

“They kind of came in with the attitude of, ‘this is Australia, not Canada, how hard can it be?’. But I remember those same guys a few days later sprawled out on the lawn here, totally spent. They just didn’t get how extreme the terrain out there is.”

Joynt, too, has heard the conspiracy theories around town that perhaps the young man staged his disappearance, explaining why no trace of him has been found.

But having been lost in the same area herself while on the Hannel’s Spur Track, stumbling on a road shivering, miles from her intended route and sobbing with exhaustion, she doesn’t believe Prabh’s whereabouts were part of a set-up.

“The country out there is just horrendous and the scrub is just phenomenal. If it could happen to me, it could easily happen to someone with less experience, and finding him out there would be like finding a needle in a hay stack.

“The sad truth is that when searches like this start, people almost never come back alive. Look at the snow boarders, look at what happened to Simon Crean’s brother.”

In August 1985, Stephen Crean, brother of the former Labor leader Simon and son of former Treasurer Frank Crean, disappeared during a blizzard when setting off on a ski trip from Charlotte Pass. After two years of searching, police at Khancoban received a package in the post containing the missing man’s wallet and identity cards and a birth certificate.

Investigations led them to Shepparton in Victoria where they arrested 26-year-old New Zealand fruit picker Stephen James Forsythe, who had stumbled upon a skeleton while walking in Kosciuszko and had reportedly removed the skull.

Police later told the Cooma local court Forsythe had deliberately tried to mislead them as to the location of the skeleton because he intended to return and collect the rest of the bones to take back to New Zealand.

Kosciuszko Huts Association member Peter Hosking was another who answered the Srawns’ call for help. He led the family on a search of the rugged Hannel’s Spur Track area, but was turned back by the rough conditions. He believes it is quite possible the young man may have headed into the area, and says despite the thick vegetation it is likely someone will stumble upon evidence of what happened to him.

“It makes sense that if the weather is really bad, the natural thing to do is head downhill to get away from the conditions, especially if you have survival training, like he did. There was a lot of pressure from different people at the time, and that’s understandable because they were frustrated at the lack of results, but I think the chances are good that one day someone will find him.”

Throughout the ordeal family members refused to give up hope of finding Srawn, spending hundreds of thousands of dollars of their own money paying rescuers to continue searching. Six months after her son went missing, Devinder Srawn told Canadian news organisation CanIndia she would never to give up.

“I won’t be at peace and neither will I rest until we find out what happened to my son. Every time the phone rings or someone comes to the door, my heart pounds.”

When contacted by Fairfax Media, the family declines to comment any further, saying they are in the grieving process and don’t think talking to the media will be helpful for their situation.

Back in Queanbeyan, Superintendent Smith says there have been no new leads, but police will not close the book on the matter.

But for now their immediate concern is ensuring there is not a repeat this winter, warning all those headed into the area not to go alone, to take suitable clothing and emergency beacons and other equipment, and to notify authorities of their trip intentions at the Parks office in Jindabyne.

“[We] threw everything we had at it; everyone who’s looked at it says we did everything the right way, and we used the right people. We went well above and beyond what our survival expert says was possible.

“There won’t be any more dedicated searches towards this matter, however we have a number of alpine operators within this command that are well aware of it. I’m hopeful one day someone will find him.”

- Additional reporting by Tom McIlroy