An Adelaide man held captive, assaulted and subsequently murdered is now thought to have been killed in South Australia's mid-north.
Police say after being detained for up to a week at a house in Adelaide's south and then at another property, it is now believed Robert Atkins was taken to the Port Pirie area where he was killed and his body disposed of.
A search has already been conducted on a rural property at nearby Booborowie and Detective Inspector Brett Featherby said investigations are continuing.
"We're in the process of narrowing down the search areas," he told reporters on Friday.
"Once we have narrowed down those areas we will conduct an extensive search to find Robert's remains."
Mr Atkins was involved in the local street-level drug scene and Insp Brett Featherby said it was that involvement that police believe led to his killing.
He was known to have drug debts, but they were not considered significant.
The 29-year-old was reported missing by his mother in January but checks have found no activity on his phone or through his bank accounts since mid-November last year.
Insp Featherby said after being held against his will and assaulted, he couldn't imagine the fear that would have been going through Mr Atkins' mind at the time.
"It would have been horrific," he said.
Detectives believe more than one person was involved in the murder and police have also seized two cars, a black Jeep Cherokee and a silver Nissan Pathfinder, for forensic testing.
They have called for people with information about the movements of those cars to come forward.
