The mysterious disappearance and suspected murder of two secret lovers on a camping trip is 'very, very close' to being solved, according to the police officer leading the search for the missing couple.
Russell Hill, 74, and Carol Clay, 73, have not been seen since quietly sneaking away for a trip to Victoria's remote Wonnangatta Valley on March 20, 2020.
Detectives now suspect the couple may have been murdered by another camper who torched their campsite to cover their tracks.
Police earlier this week released images of the charred remains of a battery, chairs and a bucket from their campsite as they hunt for a mid-1990s model Nissan Patrol 4WD seen leaving the valley that weekend.
Victoria Police Chief Commissioner Shane Patton said on Thursday he was confident officers would solve the 20-month long missing person investigation.
Russell Hill (pictured, left) and Carol Clay (right) are believed to have been murdered during a camping trip
Mr Hill's white Toyota Landcruiser (pictured) was found with minor fire damage at their burnt campsite near Dry River Creek Track in the valley on March 21
'We are getting close, very very close,' he told ABC Radio.
Detective Inspector Andrew Stamper said the 'best theory' was that the driver of the Nissan Patrol may have had a 'confrontation' with the elderly couple over a camping spot by the river.
Their burnt out belongings were found in an odd location, away from the best spot that would have been picked by a veteran camper like Mr Hill.
Police found the charred remains of camping chairs, a battery and a gas canister bucket inside the couple's tent.
Detectives believe it is unlikely the couple would have put them there and were moved into the tent by the killer before he set fire to the scene.
'It's a theory, but it's probably the best theory we've got at the moment,' Mr Stamper admitted.
'The only reason we can assume that Russell didn't camp in the best spot, was potentially there was somebody already there.
The mid-1990s model Nissan Patrol (pictured) is now central to the investigation because painstaking video analysis has managed to account for every car exiting the remote valley that weekend - except the blue 4WD
The bucket (left) was used for Mr Hill to put his gas canister in and like the battery (right) , they were unlikely to be brought inside the tent where they were found by detectives
The charred remains (pictured) from the couple's campsite have been released for the first time
'There's been some sort of argument and maybe it's escalated from there.'
The camping site the suspected killer is believed to have set up at in March last year had been sought after among those who entered the rugged section of bush.
Nestled upon the river, it is a camping site Mr Hill liked to use while there on previous occasions.
But when police found his gutted tent, it was not in that perfect camping spot, but some 100 metres away.
Police found a burnt out scene at the couple's campsite last March (pictured), but no trace of the elderly campers
Mr Stamper, who only recently travelled back to the camping site himself, said Mr Hill would have bumped into the other camper as he went to the river to retrieve water.
'We believe, that based upon what we know about Russell and how passionate he was and how experienced he was in that area and the camp in general, that it would make sense for him to go to a certain position which has access to the river, a nice little campfire already made-up, but the position that he actually chose ... is not as good,' he said.
'The only reason we can assume Russell didn't camp in the best spot was potentially there was somebody else already there.'
Missing Person Squad Inspector Andrew Stamper on Monday. He believes police have made a major break through
Mr Stamper said if Mr Hill's interaction with that camper became confrontational, he would have been unlikely to have taken a step back.
'We know that Russell, albeit a very peaceful and law-abiding man, he worked in the wilderness in that area,' he said.
'He worked tough jobs so he wasn't someone who would ... take a backward step. So there has been some sort of argument and maybe it's escalated from there.'
The 4WD (pictured in a police sketch) has roof racks, side steps, off-road tyres and a bulbar. The box trailer is 'fairly standard' but has been fitted with 'off-road wheels'
While Mr Hill had made contact with a mate over his CB radio upon reaching the camp site, he made no mention of anyone else being there or any such conflict.
Police were unable to locate any clues from the other camper's site.
An image of the camper's vehicle was captured by cameras used to identify people entering the rugged terrain in an effort to keep track of who is on the mountain for their own safety.
But Mr Stamper would not reveal if the cameras had captured the vehicle's registration plate.
'The image we are releasing is the best image - I don't want to go too far into what we've got, but that's the best image
