Detectives will be searching a remote part of the state’s mid-north where they are hoping to find the young man’s remains.
Security footage from November 2020 shows Mr Atkins at the counter of the Harvey Norman in the Gepps Cross homemaker centre in Adelaide’s north on the day before police believe he was murdered.
Police said he was likely under the control of another man who was forcing him to use a stolen credit card.
Robert Atkins’s mother, Trish Spencer, is now trying to retrace her son’s final movements.
“I think he would be terrified. He would be absolutely scared to death,” Ms Spencer said.
Police suspect Mr Atkins was kidnapped by a gang of criminals — who initially held and tortured the 32-year-old over a small drug debt — a week before he was spotted at Harvey Norman.
“We know he was assaulted with a torch as well as a baton within the address at Christie Downs,” Detective Sergeant Jarrad Parker said.
Police also believe Mr Atkins was held at homes in Seaford and North Plympton before being taken to Gepps Cross where it was believed he was blackmailed into committing crimes.
“We think Rob would have had a really good idea of what these people were like and what they’re capable of and that’s why we believe that he was doing as he was told,” Sergeant Parker said.
Police revealed Mr Atkins was loaded into a Nissan Pathfinder by a lone man late on November 15, 2020.
He was then driven to Port Adelaide where a stolen credit card was used to purchase alcohol.
From there, police said the car travelled north to Booborowie before turning west and arriving in Port Pirie just after midnight.
They say the suspected killer remained there with associates until after sunrise on November 16 when the car headed through Laura and eventually to Orroroo, where police believe Mr Atkins was murdered and his body dumped.
“We certainly are making progress in that and we’re hoping that pretty soon we’ll be able to go out and physically conduct a search of an area,” Sergeant Parker said.
Ms Spencer is urging anyone with information to contact police.
“They need to be honest and go in and tell their story.”