The body-hunter expert who helped locate the remains of murdered Queensland schoolboy Daniel Morcombe has told the William Tyrrell inquest he searched a rubbish dump and creeks for the toddler’s body.

He said he didn’t find the boy’s remains, but admitted animals could have removed them like they do with kangaroo carcasses.

Water and soil scientist Professor Jon Olley headed the search for ‘cloth or bone’, or any remains of William, in an area where police believe William was dumped, which included a neighbour’s rubbish tip.

He said the rubbish dump ‘was active from the property owner at the time when William went missing’.

Prof. Olley, an effluvial geomorphologist at Griffith University, said the boy’s remains would be caught up if dumped in the creeks along a road in Kendall, below the house from where William vanished in 2014.

‘If something found its way into a creek, it would be trapped … either in shallow zones or trapped by vegetation dams,’ he said.

‘It would very difficult for anything to be washed any distance .’

Prof. Olley said polyester clothing, like the Spider-Man suit William was wearing when he vanished, would last for ‘hundreds of years’ and retain its colour in the soil.

He said a very thorough search of the area mainly found kangaroo bones, but agreed that human remains could have been removed by animal predation.

He said he had been told by a fellow scientist that William’s body or bones could ‘absolutely’ have been taken by animals.

‘There were less kangaroo bones found, [but] less than what you might have expected along the roadside,’ he said.

‘We were finding … kangaroo bones, but the rest of the carcass was missing.’

Professor Olley has previously been an adviser in site excavation for the remains of 14-year-old Marilyn Wallman, who disappeared in 1972 in Mackay.

He was also involved in the 2013 murders of Robert Martinez and Chantal Barnett in Queensland, and the search for Nathan Booth, who disappeared in 2015 in the ACT.

The inquest is probing the police theory that William Tyrell’s foster mother buried his body in bushland after he fell from a balcony and died on the morning he vanished.

‘That’s the reason we’re here,’ counsel assisting, Gerard Craddock SC, told Monday’s resumed hearing into the three-year-old’s death, who was last seen in Kendall on the NSW mid north coast in 2014.

‘The theory [is that] William must have died at [his foster grandmother’s home at] 48 Benaroon Drive [in Kendall],’ said Mr Craddock.

‘The theory… police assert is that she must have quickly resolved that if the accidental death of William was discovered she might lose ‘Lindsay’.’

Lindsay – not her real name, which can’t be revealed for legal reasons – was another foster child in the care of the foster mother at that time, who also can’t be named.

‘Police assert that in that frame of mind, [the foster mother] placed William in her mother’s car,’ said Mr Craddock.

‘After alerting [a neighbour] to William’s disappearance, [she] drove her mother’s car to Batar Creek Road and placed William’s body somewhere in the undergrowth.’

Mr Craddock told the hearing on Monday that the foster mother had no recollection of the precise time she drove her mother’s car from the house after the boy vanished on the morning of September 12, 2014.

The inquest’s chief counsel also told the hearing on Monday that he cannot confirm the foster mother’s claims of seeing ‘strange cars’ in the street.

Both William’s biological father and his foster parents are attending the hearings, as are detectives from Strike Force Rosann, and its boss Detective Chief Inspector David Laidlaw. 

The long-running inquest into the 10-year mystery will also hear from Professor Jon Olley, a water science expert who was onsite at the renewed hunt for the toddler body in a fresh dig staged in 2021. 

Mr Craddock said the area around Batar Creek Road had been extensively searched by police who did not believe any trace of William was left there.

He also said that in the search for William after his disappearance – with police, fire fighters, cadaver dogs, chainsaws and hydraulic equipment – meant that the little boy had not simply just been lost in the search area.

‘William under his own steam could not travel beyond the area of the intensive search,’ he said. ‘The conclusion there must have been human intervention.

‘It’s beyond argument that no eye eyewitness can provide an account about how he left the boundaries of 48 Benaroon Drive.’

The inquest, which began in 2019 but has been beset by protracted delays has now entered its final block of hearings, which will be held this week, and over two weeks just before Christmas.

William’s disappearance has become one of Australia’s most notorious missing persons cases.

The inquest before Deputy State Coroner Harriet Grahame – examining William’s disappearance and suspected death – was delayed last year when prosecutors weighed up charges against the boy’s foster mother.

William’s foster mother and father have continuously denied the allegation they played a part in his disappearance or any wrongdoing.

The inquest originally began in 2019 and ran for 18 months before it was adjourned in October 2020 and Ms Grahame’s findings were due to be handed down in June 2021.

The inquest was pushed back for police to begin the fresh investigations in late 2021 that involved searching new locations around Kendall.

On the fresh dig, teams scoured the garden of his foster grandmother’s home and nearby bushland, but did not report finding anything of significance. 

The inquest was then pushed back again, as prosecutors weighed up the evidence concerning the missing boy’s foster mother.

Last year, police handed a brief of evidence to the Director of Public Prosecutions that recommended William’s foster mother be charged with perverting the course of justice and interfering with a corpse.

 Around that time, the foster parents’ solicitor Rylie Hahn called for police to disclose any evidence. 

‘William’s foster mother and foster father hold the position of calling for the disclosure of evidence which police suggest forms the basis of criminal proceedings,’ Ms Hahn said last year.

‘We are midway through the inquest and William remains missing and his case unsolved.

‘William’s foster mother maintains she had nothing to do with his disappearance … and asks the police to continue to look for William and what happened to him.’

Then in August this year, Ms Grahame was handed a letter from the DPP, outlining the status of that request for advice.

In the letter, the Director of Public Prosecutions, Sally Dowling SC, said that NSW Police had in April asked her office to ‘suspend’ its request for advice until the conclusion of the final block of inquest hearings. 

In 2022, William’s foster mother was found not guilty of lying to the NSW Crime Commission.

In November last year, William’s foster father was also acquitted of five counts of lying to the NSW Crime Commission.

The court was told at the time that during the Crime Commission hearing, counsel assisting, Sophie Callan SC, questioned the foster mother about whether William had fallen from the balcony and she had disposed of the body.

The couple denied any wrongdoing or disposing of his corpse.