The extensive search for four-year-old Gus Lamont, who went missing in South Australia, has concluded without any findings, as police and military personnel were unable to locate the child.

The search, dubbed Task Force Horizon, entered its fourth day today, concentrating efforts within a 5.5-kilometer radius surrounding the remote Oak Park Station homestead, where Gus was last seen.

This week, search teams covered an area of 95 square kilometers on foot.

Previously, the search had expanded significantly, utilizing both the mounted operations unit and Polair to sweep through an estimated 470 square kilometers.

This afternoon, police confirmed that no evidence of Gus has been discovered.

“Given Gus’s young age, coupled with the challenging terrain, which is extremely rugged and subject to fluctuating weather conditions, the search has been particularly arduous,” stated the South Australian Police in an official release.

“Each of these factors may have contributed to the lack of evidence discovered. The location also presents less opportunities for police searching for a missing person, compared with an urban environment.

“Police have been making every effort to return Gus to his family through detailed, meticulous and protracted searching of the property and this remains a priority.”

The search for Gus has been one of the largest of its type carried out by SA Police.

Police say further searches will be considered.

SA Police said the family of Gus Lamont were continuing to cooperate fully with police and were being supported by a victim contact officer.

Gus was last seen about 5pm on Saturday, September 27 at his family’s homestead Oak Park Station in remote South Australia, about 40km south of Yunta.