Two members of Gus Lamont’s family have hired separate lawyers, as police revealed their only suspect in his disappearance and presumed death was known to him but not one of his parents.

Gus went missing from Oak Park Station – a 60,000ha remote South Australian property about 40km south of Yunta – on September 27 last year.

An air and ground search of a scale unprecedented in the history of South Australian Police failed to turn up any trace of the four-year-old, and investigators later returned to forensically search the homestead on January 14 and 15.

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It was revealed on Thursday night that Gus’s grandparent, transgender woman Josie Murray, had reportedly hired Adelaide criminal lawyer Andrew Ey, while the boy’s grandmother Shannon Murray had sought the legal services of Casey Isaacs, also from Adelaide.

Mr Ey is a partner at Mangan Ey & Associates and has been involved in a number of high profile criminal cases throughout his more than 15-year career.

He successfully defended Australian Idol contestant Shannon Noll when he was accused of assault outside Adelaide’s Crazy Horse nightclub in 2017.

Mr Isaacs is from Caldicott + Isaacs law firm and is also the president of the Australian and New Zealand Association of Psychiatry, Psychology and Law.

The partner confirmed he had been engaged by Shannon, telling The Advertiser: ‘We have been co-operating but we won’t be commenting’.

The suspect in the disappearance and suspected death of four-year-old Gus Lamont (above) lives on his family's remote South Australian property but is not either of his parents
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The suspect in the disappearance and suspected death of four-year-old Gus Lamont (above) lives on his family’s remote South Australian property but is not either of his parents

Oak Park is a 60,000ha property (pictured) near the community of Yunta
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Oak Park is a 60,000ha property (pictured) near the community of Yunta

Detective Superintendent Fielke did not disclose the identity of the person who is now considered a suspect in Gus's disappearance
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Detective Superintendent Fielke did not disclose the identity of the person who is now considered a suspect in Gus’s disappearance

Police have not made any arrests or laid any charges. It is common for witnesses to seek legal advice and it is not suggested either were involved in any wrongdoing.

Detective Superintendent Darren Fielke said on Thursday that from when Gus first disappeared ‘the family members have been cooperating with police’.

He said those family members had provided information that ‘assisted with establishing the movements of Gus’ around the time that he vanished.

‘A detailed review of all of that information has been conducted by Task Force Horizon members,’ he said.

‘We have identified a number of inconsistencies and discrepancies with that information as it relates to timelines and the version of events provided to us by the family members.

‘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.’

Detective Superintendent Fielke did not disclose the identity of the person who had withdrawn their support but said that person was now considered a suspect in Gus’s disappearance.

‘I do want to stress, however, that Gus’s parents are not suspects in his disappearance,’ he said.

Gus Lamont's grandmother Josie (pictured)
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Grandmother Shannon Murray is pictured
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Seen outside the family’s Oak Park sheep station in November, Gus Lamont’s grandmothers Josie (formerly Robert), left, and Shannon Murray, right, attend a meeting at a café 90 minutes from their Yunta home, in Peterborough, South Australia

Gus went missing from the property on September 27 last year. The station is pictured
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Gus went missing from the property on September 27 last year. The station is pictured

‘What I can say, however, is that we’ll continue to thoroughly and meticulously investigate the disappearance of Gus until we get an outcome.’

Detective Superintendent Fielke, who confirmed police do not believe Gus is alive, said he could not elaborate on the ‘discrepancies’ in information provided by family members.

Police have previously said on the day Gus disappeared he was in the care Shannon, who had seen him playing in sand outside the homestead about 5pm.

Gus’s mother Jessica and Josie were tending sheep about 10km away, while his father Joshua was not living at Oak Park and not present when his son disappeared.

When investigators returned to Oak Park last month a comprehensive forensic search was conducted at the homestead.

A vehicle, a motorcycle and some electronic devices were seized on January 14 and 15 and are now being forensically tested.

Asked whether the suspect was still living at Oak Park, Detective Superintendent Fielke said: ‘I can’t give you any more information about the suspect or where the suspect is and why that person is a suspect.’

Detective Superintendent Fielke described the investigation as ‘delicate’.

‘A person – we have a suspect – who we believe is known to Gus,’ he said.

‘So, I’m not going to speak too much about that at all. But I can tell you that Task Force horizon members, myself, are very cognisant of how delicate that is, and what that means for the family.’