Police believe suspected murder victim Robert Atkins was walked out into remote bushland in South Australia's Mid North and killed by a man who was familiar with the area.
Detective Superintendent Des Bray said over recent months police had been able to narrow down a very large search area to about 10 square kilometres within which they believed Mr Atkins's remains would be found.
"The investigation has progressed extremely well to the point that we know the routes Robert went in his final hours," he said.
"We believe that on Robert's final day he was brought to an area very close to where we stand and he was walked into the scrub where he was murdered.
"We believe that the offender most likely did a very lazy concealment on the day and most likely covered Robert's body with some loose brush before returning several days later to this area.
About 40 officers began searching an area between Peterborough and Orroroo this afternoon on foot and using motorbikes.
The investigation into Mr Atkins's death has led police to the region before, but this is the first time every square kilometre of a specific area will be physically searched.
"We will take as long as it takes to thoroughly search this area and be confident that we have either found Robert's body or that his body is not in this area," Superintendent Bray said.
"If that should happen, there are other areas out further where we also need to search, but they have all been prioritised and they will be done in the coming days and weeks if necessary."
Superintendent Bray said one suspect who police believed was directly involved in Mr Atkins's death was from the Mid North originally.
"It's difficult to know whether when Robert came here or whether he was brought here under pretence and coercion or another reason, but we do know that in his final moments he was walked into the scrub most likely against his will and that's where he was murdered."
Police have previously said they believe Mr Atkins's death was connected to his involvement in the drug scene in Adelaide's southern suburbs.
One of the state's largest task forces was set up in December to investigate his death, along with other unsolved suspected murders in SA in which police believe the victims were targeted over petty drug debts.
"Some of the people involved are in custody for other offences and have been arrested during Task Force Southern," Superintendent Bray said.
"There's a lot of people who know what happened."
Superintendent Bray said it was "completely achievable" to find Mr Atkins's remains within the search area.
"I've been disappointed lots of times before. I'm as confident as you can be and we have committed a lot of resources to finding him and we wouldn't commit the resources if we didn't think there was a good chance," he said.
"It's horrible to lose a loved one in any circumstances. If it's a violent death it's worse, and it's worse again if they're not recovered.
Mr Atkins was reported missing by his mother in January last year but police believe the 29-year-old was murdered in November 2020.
Detectives allege he was held captive for more than a week and tortured in a Christie Downs home before he was killed over a $1,000 drug debt.
The search will resume at 7am tomorrow.
