Abandoned mineshafts, tunnels, and an outhouse on the Oak Park Station property have been examined by police as they continue the search for missing four-year-old Gus Lamont.

The latest search for evidence at the family’s property has concluded with police saying “no evidence was located”.

Numerous buildings and structures at Oak Park Station and adjoining locations were searched, including mineshafts, underground tunnels, and an outhouse where fresh cement was recently laid. A remote section of a sheep station and a water tank were also searched.

A cadaver dog trained to detect human remains was brought in from New South Wales to assist the search, as well as a police helicopter.

Police later moved to a property at Grampus, about 24 kilometres from Oak Park, where major crime detectives were seen combing through the yard and homestead. No evidence connected to Gus’ disappearance was found at either location.

Despite concluding the search empty handed, detectives have “not ruled out returning to Oak Park Station as the investigation continues.”

Numerous buildings and structures at Oak Park Station and adjoining locations were searched. Credit: SAPOL

Gus was last seen on September 27, police were told that he was last seen playing outside the main homestead while his grandmother cared for his younger brother inside.

Major Crime’s officer in charge, Detective Superintendent Darren Fielke, confirmed police cannot rule out that Gus was still on the 60,000-hectare property when officers reached the homestead on the night of September 27.

Numerous buildings and structures at Oak Park Station and adjoining locations were searched. Credit: SAPOL

“Police were on scene quite quickly when they were advised that Gus was missing.

“Yes, there was some time in between, but it is possible.

“We’re still working on that (original) timeline.”

The timeline put forward is now under intense scrutiny.

New photos reveal gruelling search for missing Gus Lamont Credit: SAPOL

“I haven’t been briefed on the exact offences that are the subject of the charges. It is my assumption that they relate to either storage, ammunition, registration licensing,” Police nMr Stevens said when asked about the specific charges relating to firearms at the Yunta homestead.

“Anyone who holds a firearms licence has to demonstrate they have a genuine need for the firearm. In order to obtain firearms you have to have that approval.

Police talk to Josie Murray during a search. Credit: 7NEWS/7NEWS

“The Firearms Act permits us to enter any property where we understand there are firearms or there is registered firearms or a person who has a firearms prohibition order. When it comes to the investigation of other offences we use a warrant for entry onto the premises.”

Josie Murray is set to appear in the Peterborough Magistrates Court on May 6.