A two-day search at the remote property where four-year-old Gus Lamont vanished has concluded without police finding evidence.
A cadaver dog was brought from interstate to assist in the latest search for the boy, who was last seen by his grandmother playing at the Oak Park Station homestead in South Australia's Mid North on September 27.
The search covered numerous buildings and structures at the station and at several locations adjoining the property.
Officers inspected an outhouse with fresh cement and a water tank at a neighbouring property, the ABC reported.
"Today's searches involved Polair and a cadaver dog from interstate to assist in locating human remains," police said.
"Unfortunately, no evidence was located during the intensive searches."
Police announced on Monday that they were returning to the station for two days "to continue searching for evidence".
On February 5, police declared Gus's disappearance a major crime and said someone living at the remote station was a suspect in the case and his likely death.
They confirmed the boy's grandparents, his mother and his younger brother were at the property at the time he disappeared but emphasised his parents were not suspects.
Gus's grandparents Josie and Shannon Murray released a brief statement via their lawyers saying they were "absolutely devastated" by the police statements.
Investigators searched the station homestead on January 14 and 15, seizing items including a vehicle, a motorcycle and electronic devices for forensic testing.
Gus's disappearance sparked intensive searches spanning almost 500 square kilometres and involving hundreds of police and volunteers as well as aerial support and mounted units.
