The grandmother of missing toddler Gus Lamont has lashed out at police in a bombshell interview, claiming she was wrongly treated as the prime suspect while officers missed clues a stranger was on her property the day he disappeared. 

Gus, 4, disappeared from Oak Park Station near Yunta, South Australia, on the evening of September 27, with his grandmother Josie Murray among the first to notice he was missing. 

Ms Murray claimed detectives dismissed a moved bed stand and weather station, boot prints and wheel tracks as evidence someone else had been in the area when he vanished.

However, she told Spotlight the first mistake was made before the investigation had begun, claiming one officer didn't even turn up after she called police at 8pm that night.  

'After (Luke the first officer) arrived, there was a second one on his way,' Ms Murray said.

'Luke and I were sitting on the hill outside the house trying to spot (the second officer's) flashing light and this went on for some time.

'(I tried) to describe how he should get to the property... and eventually he just gave up and went back... so he actually never arrived on the property.'

The morning after he went missing, Ms Murray said she noticed the bed stand next to the house had moved as well as the weather station. 

'I remember looking out the window because it was starting to get light by that stage and there was a bed stead which had been moved,' she said. 

'Not quite 180 degrees, but a substantial amount to when I last saw it. 

'It was heavy and a child would not have been able to shift it. 

'I also saw the weather station had been moved... but I'm not sure when that happened.'

That was one of the first signs she felt Gus was abandoned, but when she saw tire tracks going past the bed stand and weather station, she said her suspicions grew stronger. 

'These wheel tracks were (from a) small tire, medium sized car with not much tread on them, not an off-road type tread and  it was definitely a passenger type,' Ms Murray said. 

'I thought that's strange too, and I started to think almost immediately, I wonder if someone's come in.

'All the time I was thinking, you know, there's a chance that he's been taken by someone.'

When she took a closer look at the dam near the property, she said she also saw what seemed to be Gus's footprint. 

However, police dismissed it as proof before later admitting to her they shouldn't have.

'I found these footprints near the dam,' she said. 

'The dam was nearly dry, it was mostly mud, and we actually took one of Gus's boots out there and I took it, laid it next to this footprint and took a photograph of it and I said it's gotta be him because it's the right size.

'The police kept on saying that no and that it was a police diver.

She said she also told Luke to not rule out abduction as a possibility. 

'I'm pretty sure I talked to Luke McCoy and said look, don't rule out, abduction,' she said.

'There's signs that something has occurred in front of the bomb shelter, and that was where Gus was when we last saw him and we're suspicious.'

Many vehicles drove up to the property in the days that followed, searching for Gus and for evidence, which Ms Murray felt was a bad idea.

'My immediate thought was my god they've destroyed any chance of tracking him if he'd walked out on the road or anything because the road was already pounded up, starting to get dusty, and they'd made a mess,' she said.    

Ms Murray revealed that detectives later admitted to her she was right and that they had made another mistake.

'They admitted to me later they think it was a mistake to come in with all those vehicles so early when they should have gotten a guy from Port Augusta who had been at our place catching dogs and trapping them,' she said. 

'We needed to get him there while there was still a chance to find his track and he arrived three days after.'

Besides from being unhappy with the way the investigation was handled, Ms Murray said she also found it 'ludicrous' that detectives later labelled her as the main suspect as they believed she had buried him after he had an accident.

'To think I could go out there and do something like that, to think I'd be stupid enough to do it is ludicrous,' she said. 

'To think I could face the trauma of doing that would also be ridiculous.'

She said that if that had been the case, it wasn't impossible not to be caught given the conditions at the open, remote and distant area.  

'When it's so dry and dusty like that, there's no way you can bury something without leaving evidence that the ground has been disturbed,' Ms Murray said. 

'The amount of searching that went on with a helicopter, with the fixed wing, with the drones, with everything, you would see signs of someone being buried.'

Even if she had thrown Gus into the dam, investigators would have found out. 

'I mean obviously they were thinking about the dam and I had several neighbors who said to me afterwards it would be again ridiculous to think that he'd gone into the dam,' she said.

'There was weed all around the dam and if anything had gone in there, you would disturb that weed and it'd be obvious.'

7News Adelaide crime reporter Hannah Ford said on the show police had 'almost certainly ruled out abduction because they believe it is so unlikely that a stranger would be so opportunistic to go into a property so remote'.

According to Ms Murray, one of the two main reasons police felt there was no chance of abduction was that 'there was only four-wheel drive access to Oak Park, which she described as 'laughable'. 

'That's absurd because the Hilux they've taken down there to do tests on is a two-wheel drive,' she said. 

'Shannon (Gus's other grandmother) has a two-wheel drive, Jess has got a two-wheel drive, the buggy's a two-wheel drive,' she said. 

She claimed the other reason was that cameras didn't show signs of any other vehicle entering, which she also described as 'laughable'. 

'The other thing that they said was that the footage on the security cameras on the property next door where you come in from Yunta Road showed that no-one had come out to Oak Park in that time frame,' Ms Murray said. 

After she identified the camera showed the part of Oak Park they called Breakneck Creek, she said they couldn't have known because she claimed she was told the camera 'wasn't working at the time'.