By Daniel Keane and Sophie Holder for ABC News
Emergency services have entered the fifth day of searching for Gus. Photo: ABC News / Daniel Taylor
The search for a four-year-old boy who remains missing in South Australia's north days after he disappeared is shifting towards a "recovery" phase despite the discovery of a footprint, police have said.
The boy, Gus, was last seen playing in sand at his family's remote sheep grazing station on Saturday about 40 kilometres south of Yunta.
Superintendent Mark Syrus - officer in charge of the Yorke and Mid North region - said police had discovered a footprint about 500 metres from the homestead on Tuesday.
He said it was a "very similar boot pattern to what Gus was wearing when he went missing", and that a tracker had since been called in.
But Superintendent Syrus said police had spoken to the family about potential outcomes.
"We always hold out hope that he's a tough lad and he's crawled under a bush and he's still alive but we're just preparing the family for the fact that we may be moving from a search effort to a recovery," he said.
"Gus has been now missing for now into the fifth day, 84 hours, and a young boy without food, water, shelter for that period of time - it's going to be pretty tough on that little lad."
A tracker (pictured) has been called in to help in the search for missing four-year-old Gus on a rural property near Yunta. Photo: ABC News / Daniel Taylor
Superintendent Syrus said 40 police cadets would today join the search, and said the footprint was the first indication of "which way Gus might have gone".
"As a result of that we've actually brought in a person with some specialist skills in tracking and who's got a very close connection to the land out here," he said.
"He came in here early afternoon, worked throughout the afternoon, just driving around the area looking at the country and he's back here, back out in the field, assisting police and emergency services in trying to find a direction [in] which Gus walked.
"[The footprint] does start to refocus our search but we've got to be very careful that we don't throw all the resources into that, and not look at other areas of high probability as well."
Addressing the media at midday, Superintendent Syrus said the tracker had "worked in this property and he knows it quite well".
He also elaborated on the footprint find, and said it was discovered by one of the ground searchers.
"We actually didn't find any other tracks after that - it has been windy up here for the last couple of days," he said.
The terrain around where Gus was last seen is vast and rugged. Photo: ABC News / Daniel Taylor
Superintendent Syrus said members of SA Police's Major Crime unit had arrived at the scene but was quick to point out there was "no suggestion of anything suspicious".
"As any part of any search there's an investigational process so they're just doing their due diligence," he said.
"When searches happen we always have an investigational component of it and they're just here … to see if there's anything we have missed, and they're part of the missing persons unit as well."
'Our hearts are aching'
On Tuesday, a statement was released by the boy's family in which they said they were "devastated by the disappearance of our beloved Gus".
In the statement - which was read by family friend Bill Harbison, who went to school with Gus's grandparents - the family said they missed Gus "more than words can express".
"Our hearts are aching and we are holding onto hope that he will be found and returned to us safely," they said.
Police are confident Gus was on the property and has not been taken, so a photo of the boy has not been shared, but police have released an image of a shirt he was wearing.
SA Police shared an image of a 'Minions' shirt which is similar to the one four-year-old Gus was wearing when he went missing. Photo: Supplied / SA Police
"He was last seen wearing a grey sun hat, a cobalt blue T-shirt featuring a yellow 'Minion' character, light grey long pants, and boot," police said.
He is described as Caucasian with long, blond curly hair.
On Wednesday, Superintendent Syrus said the suspicion remained that he had "wandered off", but said police had not "discounted" the further "theory" he could have been attacked by an animal.
He said Gus disappeared about 5pm on Saturday.
"The family had a look around for him and after about three hours they couldn't find him and so they alerted police," he said.
"Police were out here about 9:30pm Saturday night and we've maintained a presence since then."
Community spirit 'shining so brightly'
Acting Senior Sergeant Pete Williams told ABC Radio Adelaide said the public response to Gus's disappearance had been "truly remarkable".
"The spirit of the community in this one has been shining so brightly over the last few days, it's been incredible," he said.
"Hundreds and hundreds of community members have all come together united by the hope of trying to find Gus and bring him home.
"There are literally hundreds of people calling our call centre, calling our comms operators, providing their details, offering ATVs, offering horses, offering every imaginable thing."
Mounted operations have been assisting in the search for missing 4-year-old boy Gus. Photo: ABC News / Daniel Taylor
ABC reporter Bethanie Alderson has been on the scene since Monday and said authorities were working in trying conditions.
"The enormity of the sheep station hits you as soon as you arrive, with blue bush scattering the red dirt as far as the eye can see," she said.
"The only sign of its end is the blue, rugged peaks on the horizon. The beginning of the Flinders Ranges."
She said areas that appeared flat and smooth at first glance were deceivingly rugged and hilly terrain.
"The arid scrubland is laced with winding sandy tracks, which reveal hidden crevices and dry creek beds at almost every turn."
She said the area was dusty due to high winds, further stirred by those searching the property on motorbikes.
- ABC News
