Police unable to find single trace of four-year-old boy who went missing from family home after being left alone for half hour

He disappeared on September 27 whilst playing on a dirt mound at approximately 5pm at Oak Park Station homestead, situated roughly 300 kilometres north-east of Adelaide.

The child's grandmother discovered his absence when she attempted to summon him indoors.

His family conducted their own search for three hours before alerting authorities.

A massive 10-day operation across the vast 60,000-acre property involving state emergency services and helicopters.

South Australian police deployed advanced drone technology equipped with infrared capabilities, previously utilised in locating murder victim Julian Story's remains in a 2010 case.

Acting Commissioner Linda Williams confirmed the specialised equipment surveyed the property over the weekend, with analysis of the complex data expected to take several weeks.

"If any information comes that directs us to conduct further searches in specific areas, we will be doing that in coming weeks," Mrs Williams stated.

The operation formally concluded on Tuesday after exhaustive efforts across the sprawling outback terrain near Yunta.

Despite the comprehensive search involving multiple agencies and cutting-edge technology, investigators discovered no physical evidence indicating the child's direction of travel.

An experienced searcher who assisted the family expressed conviction that the boy was no longer within the property boundaries.

Jason O'Connell, who spent over 90 hours combing the homestead alongside his partner Jen, told the Adelaide Advertiser: "If he was in a bad way or if he passed away, we'd listen for foxes look for birds of prey.

"No birds of prey means he's not there."

Mr O'Connell described witnessing the devastating impact on Gus's father during their joint search efforts.

Assistant Commissioner Ian Parrott confirmed investigators found no tangible evidence throughout the operation.

Mr Parrott said: "No tangible pieces of evidence, such as footprints, a hat or clothing, have been located to identify any direction of travel to assist searchers."

A footprint discovered during the search was initially considered potentially significant.

However, it was subsequently ruled out as unrelated to Gus's disappearance.

Senior officers informed the family approximately one week ago that survival prospects had diminished given the child's age, the elapsed time and harsh terrain, with the search transitioning to a recovery mission within the past 48 hours.

Police leadership defended the family against online speculation, with Acting Commissioner Williams emphasising their full cooperation:

He said: "The family have continued to cooperate fully with police and have consented to every request that we have made of them thus far."

Assistant Commissioner Parrott criticised "keyboard detectives" attempting to cast aspersions on the family, urging people to consider their distress.

The investigation has been transferred to the Major Crime Investigation Branch's missing persons section, following standard protocol.