BREAKING OUTBACK ALERT — The frantic hunt for missing 4-year-old Gus Lamont has entered its most CRITICAL phase as rescuers face brutal 43°C heat and fading hope under a burning sky.

 Over 120 officers, drones, and tracker dogs have now joined the mission across 60 kilometers of rugged terrain — but sources say one mysterious footprint found near a deserted windmill could change everything.  “Every hour counts now,” one volunteer whispered. “If he’s still out there… this is our final window.”

Search for missing boy Gus continues ahead of extreme heat in SA outback

A police helicopter in outback SA during an earlier phase of the search for Gus. (ABC News: Daniel Taylor)

In short:

A renewed search for missing four-year-old Gus will continue in outback South Australia, more than a fortnight after he went missing.

More than 80 ADF personnel took part in the effort which continued on Wednesday, but no evidence was uncovered.

What’s next?

The effort is expected to continue again on Thursday, but police say “extreme heat” could “restrict searching to the cooler morning period”.

Police say a desire to leave “no stone unturned” is at the heart of their renewed search for missing four-year-old Gus, but after a second day back at a remote property they are yet to find any evidence.

An expanded search involving more than 80 Australian Defence Force personnel, as well as police and other resources, resumed on Tuesday.

As the renewed effort finished up today, police said it had again “concluded with no evidence being located”.

In a statement, police said the search would continue on Thursday, but soaring temperatures meant it would likely start and finish early.

“With temperatures of 36 degrees and strong northerly winds expected in the search area on day 3 … searching is expected to start at sunrise and conclude at midday,” police said.

An aerial view of some of the terrain near the search area. (ABC News: Daniel Taylor)

On Tuesday, South Australian Police Commissioner Grant Stevens said the total search so far had “covered approximately 470 square kilometres” and that the fresh effort extended into zones that went beyond the original area.

“When you consider that the square mile of Adelaide is about just over four square kilometres — that’s 100 CBDs, over 100 CBDs, that we are searching in quite unusual terrain, so it is a significant effort,” he said.

The so-called “square mile” of Adelaide is bordered by North, East, South and West Terraces. (ABC News: Ben Pettitt)

“The search area that was originally canvassed was established on the basis of expert advice regarding just how far a four-year-old child was likely to travel, the implications of being alone and unprotected in the environment, survivability factors and medical advice as well.

“The location we’re now searching is outside of the original … location.”

After days of initial searching yielded almost no clues, police acknowledged sadly that there was “little hope” of survival for someone so young in such terrain, and Commissioner Stevens on Tuesday described the ongoing work as partly a “recovery exercise”.

“Our hope is that we can find Gus and return him to his family because that will be an important step in their process of working through what can only be described as a tragic course of events,” he told ABC Radio Adelaide on Tuesday afternoon.

About 80 ADF personnel took part in the search on Tuesday. (ABC News: Ashlin Blieschke)

“This is a case of us making sure that we leave no stone unturned.

“Our efforts continue to be searching the property as much as possible so that we can provide absolute assurance that this has been as comprehensive as people would expect it to be, given that we’re looking for a four-year-old child.”

‘No additional information’

Gus was reported missing from his family’s sheep station about 40 kilometres south of Yunta on Saturday, September 27.

His disappearance sparked an extensive ground and air operation, described by police as “one of the largest, most intensive searches for a missing person conducted in South Australia in recent times”.

Police earlier released this photo of missing four-year-old boy Gus.  (Supplied: SAPOL)

On the Friday following Gus’s disappearance, they announced that the effort was being scaled back, but nevertheless continued to carry out “significant” searches — with a drone, and of a dam — over that weekend and into the following week.

Police have been adamant that the decision to conduct fresh efforts this week has not been “based on new information”.

Instead, they want to take “every opportunity to completely saturate any possible location” where Gus could have gone, the commissioner said.

“There’s been no additional information brought to our attention that has been the catalyst for what we’re doing today and over the next couple of days,” he said.

“[But] even without a successful result from what we’re undertaking over the next couple of days, it is our intention and our obligation to continue focusing on any possible likely factors that would have contributed to Gus having gone missing.”

A tracker was called in to assist during the first week of the search. (ABC News: Daniel Taylor)

Part of that work will be conducted by Task Force Horizon, which was announced on Tuesday and will comprise 12 experts with different skill sets.

“The team is made up of data analysts, expert search controllers, coordinators, we have investigators and other specialists that are forming up this taskforce to maintain that ongoing focus that will seek to find answers regarding the disappearance of little Gus,” the commissioner said.

The search will continue on Wednesday but “extreme heat” forecast for Thursday is expected to “restrict searching to the cooler morning period”.

“We’ll see a forecast maximum of about 37C, so the plan is on Thursday to start early, and hopefully conclude this part of our search activity by about lunchtime,” the commissioner said.

“There’ll be a continual reassessment, and the resources that we’re deploying may change over time, and the use of specialist drones will be another consideration as we move forward as well.”

Police released this photo during the earlier phases of the search. (Supplied: SA Police)

Drones have previously featured in the search, including one fitted with a thermal camera, the results of which remain forthcoming.

“We are not very hopeful we are going to get anything significant from that data but we are still waiting for the conclusion of that analysis,” he said.

One distraction had come in the form of misinformation and speculation, which the commissioner described as “incredibly frustrating”.

“We are being contacted by people who are providing theories — those theories are not always helpful,” he said.

“Some of them are easily discounted, but notwithstanding that, it still takes the time of an investigator to assess that.

Police during the first week of groundsearching in the days after Gus went missing. (ABC News: Daniel Taylor)

“They’re dealing with people who are speculating, or providing false information or inflammatory information that’s not substantiated by any evidence.

“It is frustrating and somewhat disappointing when you look at the speculation and the position it puts the family in.”