Russell Hill knew the rugged Wonnangatta Valley as good as anyone brave enough to venture that far into the wilderness.
It is bravery that police now fear may have cost him, and his secret lover Carol Clay, their lives.
On Monday, Missing Person Squad Inspector Andrew Stamper again fronted the media as police embark on what could be the final steps before making an arrest.
Russell Hill (pictured, left) and Carol Clay (right) are believed to have been murdered during a camping trip
Missing Person Squad Inspector Andrew Stamper on Monday. He believes police have made a major break through
Mr Stamper said police believe Mr Hill more than likely met foul play after getting into an argument with another camper in the remote Victorian wilderness.
That camper was believed to be driving a mid-1990s model Nissan Patrol and towing a trailer.
The camping site that person is believed to have been set up at on March 20 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 too liked to enjoy while there.
But when police found his gutted tent, it was not in that perfect camping spot, but some 100 metres away.
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.'
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 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,' he said.
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.
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 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'
The pair went missing in the Wonnangatta Valley, more than 200km north east of Melbourne
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
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 that we've got,' he said.
Police again appealed for anyone in the public who may have information on the vehicle to contact them.
The seasoned detective said time was running out for those responsible for whatever happened to the couple.
Whoever was behind the wheel of the Nissan 4WD is yet to contact Victoria Police.
The owners of a white ute, which police had been keen to speak with, had come forward and was subsequently ruled out as a suspect.
'We'll keep going. We'll never stop,' Mr Stamper said of the investigation.
The 4WD 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'.
Inspector Stamper said the killer had tried to cover their tracks by burning Mr Hill's campsite and using the trailer to move the bodies.
'My belief is that this was not planned or premeditated attack it was just something that happened quickly which probably means whoever did it would have acted quickly in trying to conceal
