Why missing campers could still be ALIVE: The unanswered questions that shed MAJOR doubt on claims married man and his glamorous companion were murdered on their secret trip
A crime expert has revealed why he believes secret lovers who vanished on a remote camping trip may not have been murdered.
Russell Hill, 74, and Carol Clay, 73, went missing on March 19 in the Wonnangatta Valley in Victoria's East Gippsland region.
Their disappearance baffled authorities, who found their campsite burned to the ground and Mr Hill's car slightly damaged by fire two days later.
Crime editor at PodcastOne Australia, Adam Shand, said he was 'not convinced' the couple are dead.
'We don't know what we don't know in this case. We don't even know that they're dead,' he told A Current Affair.
Russell Hill (pictured left), 74, and his lover Carol Clay , 73, went missing during a camping trip on March 19 in the Wonnangatta Valley in Victoria's East Gippsland region
Crime podcaster Andrew Shand said it was assumed that the couple were murdered but he was 'not convinced' they were dead. He said authorities would have found their bodies
Mr Shand said many believed murder was the 'strongest theory' but there was no lead that suggested any foul play.
MISSING CAMPERS - UNANSWERED QUESTIONS
What were the campers doing in the Wonnangatta Valley?
Why did Mr Hill not tell his wife he was going?
Why did Mr Hill take his drone?
'Today we're still scratching, at least in a public sense, for a motive if there has been a killing.'
Mr Shand also said the couple's bodies would have been discovered if they had been killed.
'You've got crows and other carrion eaters circling over those corpses. That often leads police in searches to bodies,' he explained.
Mr Shand said there were plenty of unanswered questions relating to the couple's disappearance.
'There are so many questions. Why were they there? Why was Russell there? Why did he not tell his wife? Why was he there with the drone? What was he doing?' he said.
Detectives have been consulting with interstate and global police about the investigation.
Police have also asked interstate travellers who were visiting the area at the time to come forward.
Last month police revealed they were exploring a theory that the couple were attacked in their sleep.
Detectives believe the potential attackers may have torched their campsite to destroy forensic evidence of a crime.
Mr Hill's white Toyota Landcruiser was found with minor fire damage at their burnt campsite near Dry River Creek Track in the valley on March 21
The search for Mr Hill and Ms Clay has gone international, as detectives turn to overseas and interstate experts for assistance
Mr Hill and Ms Clay were in a secret relationship and didn't tell anyone where they were going.
Ms Clay just told friends she would be gone for a few days.
In June, investigators said three theories about Mr Hill and Ms Clay's disappearance were being probed.
Foul play is strongly suspected on the balance of probabilities, but there is no evidence and no suspects.
Another possibility is that the couple were flying Mr Hill's $2,000 drone and died of exposure after getting lost off the path looking for it.
The third is that they died lost in the bush for any reason, but have not been found because wild dogs ate their remains.
Police are confident the pair did not fake their own deaths and do not believe it's case of murder-suicide.
The pair went missing in the Wonnangatta Valley, more than 200km north east of Melbourne
Russell Hill hangs onto a drone that he had with him when he went missing. The drone has not been found despite an extensive search of the area
The key to unlocking the case may have gone up in flames in a fire that destroyed their campsite.
Mr Hill's Toyota four-wheel-drive had been found by local police next to his burnt-out tent, but the pair were gone without a trace.
The vehicle itself had also sustained damage in the fire, but was still able to be driven away from the scene.
At the time, police had believed the fire was probably started by a dodgy phone charger or campfire spark and the couple had simply been lost in the forest.
But the fire could also have been lit by a thief rummaging around in the tent - or by a murderer trying to cover their tracks.
A spare set of keys was found hidden on the car, but it is believed Mr Hill took the main set with him.
Personal belongings were left in Russell Hill's vehicle, which sustained fire damage when his tent went up in flames
Carol Clay, 73, who was once the President of the Country Women's Association of Victoria, had been in a relationship with Russell Hill for many years in the lead up to their disappearance
Mr Hill's white Toyota Landcruiser was found with minor fire damage at their burnt campsite near Dry River Creek Track in the valley on March 21
That the car was locked likely indicated the pair left the campsite voluntarily, probably to go for a walk or fly the drone.
The drone remains missing despite an extensive search that ended on April 6 without anyone finding a trace of them.
Mr Hill had been a keen amateur radio enthusiast and made his last broadcast from the bush on March 20.
Police are now certain the couple died within 18 hours after Mr Hill's last message, as a passing hiker saw the burned-out campsite about 2pm the next day.
Because the couple weren't due back until up to a week later, the alarm wasn't raised for days and precious time was lost.
When questioned about the couple's relationship in April, Victoria Police Missing Persons Squad Detective Inspector Andrew Stamper skirted around the question.
'It is delicate and we are being very respectful of both families wishes and concerns here,' he said at the time.
Anyone with information is urged to contact CrimeStoppers on 1800 333 00
Victoria Police Missing Persons Squad Detective Inspector Andrew Stamper is leading the investigation into the mystery
Russell Hill and Carol Clay were last heard from on March 20, with Mr Hill's wife unaware he was travelling with another woman