Former homicide squad detective Gary Jubelin has revealed a chilling new theory about the disappearance of four-year-old Gus Lamont, as the search for the missing child resumes.

Gus wandered off from his family’s sheep station property outside of Yunta around 5pm on September 27 and has not been seen since.

All available emergency services, SES, the ADF and an army of volunteers scoured the area for 10 days, while drones and helicopters attempted to find traces of the young boy from above.

With no leads, police made the difficult decision to hand the investigation over to the major crime squad.

However, on Monday, South Australia Police confirmed they would resume the search for little Gus in a new area of the property.

“On Tuesday, October 14, police will resume searching at Oak Park Station, 43km south of Yunta, for missing four-year-old Gus Lamont,” an SA police statement said.

The ADF will again be on hand to assist as authorities return to the outback region.

Mr Jubelin, who previously led the investigation into the disappearance of toddler William Tyrrell, told news.com.au that the renewed search suggests police are now looking “further afield” for the “sake of completeness”.

“Police would be looking at, did young Gus disappear through misadventure, wander off, or was there some form of intervention, either human intervention or even, given the nature of the land out there, perhaps wildlife,” he told the outlet.

He added, “When a young child of Gus’s age disappears, it’s a horrible thing, and it has so many ramifications for all the people that knew Gus and are related to Gus. So, I fully understand why the police are doing what they’re doing.”

The initial search was one of the largest ever undertaken by South Australia Police. Credit: SAPOL

Another former policeman, Aaron Stuart, who has experience locating missing persons and escaped prisoners in the bush, also shared a chilling insight as the search continues.

“I honestly believe the answer is back there on the property,” Aaron Stuart told The Advertiser.

“Go back, rethink it, re-interview everybody, but take them back not 30 minutes, take them back a week.”

The renewed search will concentrate on an expanded area outside of the zone already combed through extensively following Gus’ disappearance on Saturday, 27 September.

A SA police spokesperson said they continue to be in regular contact with the Lamont family, who are assisting with the investigation.

Images of the smiling blonde-haired boy who was playing outside his grandparents’ home before going missing on a massive sheep station in the South Australian outback have been aired around the globe.

He was last seen by his grandmother in a blue Minions shirt playing outside on a mount of dirt.

The search has been one of largest in South Australia’s history, with authorities covering over 47,000 hectares.