For eight months it has been a mystery that has left police, the public and a heartbroken family dumbfounded.

Ever since four-year-old Gus Lamont vanished from the remote Oak Park Station in Yunta in South Australia’s far north, questions around just what happened to him have been left agonisingly unanswered.

The fair-haired youngster was last seen on September 27, playing in the vast rural property his family called home.

This week, police investigators returned to the outback site to continue a search operation that has repeatedly combed through dried-out creeks, waterways and arable land in the area.

The three-day operation across Tuesday, Wednesday and Thursday, police say, was sparked by heavy rainfall over the previous weekend.

Investigators had hoped that the sodden conditions may have washed hidden clues into plain views, unearthing previously undetectable telltale signs.

But on Friday, Detective Superintendent Darren Fielke, from SA Police’s Major Crime Investigation Branch, said no evidence had been found to indicate little Gus had been abducted.

Instead, Superintendent Fielke said one of Gus’s grandparents “remains a suspect”

“At this time, no other suspects or persons of interest have been identified at this time of the investigation,” he said.

Both grandparents continue to communicate with police only through solicitors.

Criminology expert Xanthe Weston told NewsWire there may also be other motives to the repeated visits to Gus’s last known whereabouts.

“It is clear that the police have been ramping up the pressure for some time,” Dr Weston, an associate professor of criminology at Central Queensland University, said.

“Obviously the search is very much still ongoing and they are clearly looking at a third party, so will want that third party to know they are not letting up.

“This is a young boy that is missing and the police will want to make it abundantly clear they will not stop looking until they find what happened to him.”

Gus was last seen on the outback station wearing a large-brimmed hat and a Minions shirt, which police were hoping could have been uncovered in the heavy rainfall.

And while heavy rainfall can prove a hindrance to investigations, it can also uncover hidden clues.

“It does make sense that searches be resumed after heavy rainfall as it can make some pieces of evidence more visible – things like footprints or tyre tracks can become more apparent,” Dr Weston said.

“It can also help show when the ground has been disturbed.”

How the Gus case differs

The Gus Lamont case has particularly captured the public attention due to just how much it differs from other high-profile missing child cases – such as William Tyrrell and Cleo Smith.

These two cases in particular also bear similarities to the recent tragic case of Kumanjayi Little Baby in Alice Springs.

William Tyrrell is still missing after disappearing from his foster grandmother’s home on the NSW Central Coast in 2014, while Cleo was found alive after she was taken from her family’s tent at a campsite in Carnarvon, WA in 2021.

Dr Weston said in each of these cases, the child vanished from areas with higher population density to Gus Lamont’s case.

“What makes this case so different is that other cases had proximity to public spaces that this one just didn’t,” Dr Weston said.

“With little Gus, he vanished from a very remote station. It is a very large private property where you would not have had strangers with easy access to him.

“The likelihood that a stranger would come across him by chance is infinitesimally small.

“That makes his disappearance incredibly unusual indeed,” she said.

Despite the absence of answers, Dr Weston said the police’s repeated searches indicated they were far from ready to call it a cold case.

“The police will obviously have to look very carefully at who had access to Gus in that small, 30-minute window he disappeared in,” she said.

“Other than his family, nobody will want to know what happened more than the police. Many of them will be parents themselves and will desperately want to find the answers they are looking for.

“Clearly they are not at the cold case stage just yet, but with him having been gone for such a long time the chances of a positive outcome are very, very small.

“What happened to that poor girl in the Northern Territory was absolutely awful, but it did result in an arrest and answers.

“Gus’s parents deserve to know what happened to him.

“I just hope they can find out sooner, rather than later.”

Police have repeatedly stressed throughout the investigation that Gus’s parents are not considered suspects in his disappearance.

In February, police confirmed that a person with close ties to the household “withdrew co-operation” with investigators and had since been identified as a suspect.

On Friday, Superintendent Fielke said officers would not stop looking for Gus.

“The reality is, the longer this goes on, the closer we get to not finding him,” he said.

“That is not going to stop our resolve or our determination, but it is a reality of what might happen.

“The work in trying to locate Gus Lamont remains one of the largest and most intensive searches undertaken in relation to a missing person investigation.”

Gus’s 75-year-old grandmother, Josie Murray, has been charged with unconnected firearms offences and is due to appear at Adelaide Magistrates Court on June 12.