William Tyrrell's mum: "I heard a quick, high-pitched scream and I knew he'd been taken"

William Tyrrell's foster mother has told a coroner she immediately thought "someone has taken him" when the NSW town of Kendall fell quiet and the three-year-old boy vanished without a trace, Seven News reports.

“I couldn’t hear a thing. It was silent. There was no wind. There were no birds,” she said on Tuesday at an inquest into William’s disappearance and suspected death in September 2014.

William, who was three at the time, had been playing in and around his grandmother’s home in the quiet NSW town of Kendall on the morning of his disappearance.

He was wearing a red Spiderman suit had been playing a game called “Daddy tiger” and had been roaring at his mother and grandmother, when suddenly he went quiet.

His mother went outside to investigate and said she couldn’t see his distinctive red outfit.

“My immediate thought was somebody has taken him and he’s gone,” she said.

The woman, who cannot be identified, said while searching for William near long grass and reeds she heard “like a scream”.

“When a child hurts themselves unexpectedly, there’s a scream. And it felt like a scream. And it was quick, and it was high-pitched and it was sharp,” she said.

“I got into the bush and I thought I can’t see any red, maybe I imagined it, maybe it was a bird … and I walked back.”

In a statement to police, shown to the inquest on Tuesday, the foster mother said: “William’s cry is quite distinctive when he’s distressed.”

On Monday, she said she had seen three cars on the street the morning he disappeared – including one white and one grey car parked between two driveways.

She later believed the cars were there to abduct both William and his sister.

“My heart just sank because I thought those two cars were there for both of them,” she told the court, her voice breaking as she wept in the witness box.

The woman on Tuesday said she didn’t realise until after William went missing that those two cars were gone.

“I know in hindsight that they weren’t there but whilst I was searching I didn’t. In the initial stage, it didn’t even occur to me that those cars weren’t there,” she said.

William’s foster mother also became upset when she was describing another car in the street that morning driven by a “thick-necked” man with a weathered face who had stared at her.

“You know when you look at someone and there’s that second challenge, ‘why are you watching me, I am watching you’. It was fleeting.”

The foster mother said that the police had since identified the car.

“I did have pretty intense reaction,” she said, her voice breaking. “But in terms of the person … the image we ended up with is not the man.”

She described the man as large, with a big abdomen, short red hair, “not overly tanned” and having no facial hair.

The first week of hearings will explore William's foster and biological families, when he disappeared and the action taken shortly after he went missing.

Family members, neighbours and police will give evidence. Further hearings will be held in August when persons of interest will be called to testify.

The inquest before Deputy State Coroner Harriet Grahame continues.