Il Nuovo Postiglione - Police identify suspect in disappearance of Australian boy

Police say they launched the largest search in the history of South Australia when four-year-old Gus Lamont was reported missing in late September from his family's Oak Park Station in the outback north of Adelaide.

The mystery of the missing boy grabbed headlines across the country but police now say they are treating it as a "major crime", not a missing person case.

"Every police officer and civilian was invested in the search and had only one focus -- to find Gus and return him to his parents," Detective Superintendent Darren Fielke said Thursday.

Despite hundreds of people, including police, emergency services, army, Indigenous trackers and volunteers searching for the boy, he has not been found.

"We don't believe now that Gus is alive," Fielke said.

Police said there was "no evidence, physical or otherwise" to suggest Gus had wandered off. They found no evidence, either, that he may have been abducted.

Investigators were focused on the possibility that someone who knew Gus may be involved in his disappearance.

After reviewing evidence from family members, police said they had found "a number of inconsistencies and discrepancies" in relation to the timelines and versions of events.

"As a result of these inconsistencies and investigations into them, a person who resides at Oak Park Station has withdrawn their support for the police and is no longer cooperating with us," Fielke said.

That person "is now considered a suspect in the disappearance".

The detective stressed that Gus's parents are not suspects.

The day after the police's announcement, lawyers for the boy's grandparents, Josie and Shannon Murray, released a statement to Australian media saying they were "absolutely devastated" by the development.

"The family has cooperated fully with the investigation and want nothing more than to find Gus and reunite him with his mum and dad," the grandparents said Friday, according to local media.

A.Rastelli--INP