William Tyrrell's foster father is due to testify at an inquest into the disappearance and suspected death of the three-year-old boy in a small town on the NSW mid north coast.
The man, who cannot be identified, is the first witness to be called on day three of hearings before Deputy State Coroner Harriet Grahame in Sydney.
He was with his wife and their two foster children, William and his sister, visiting the woman's mother in Kendall when the boy vanished while wearing his beloved Spiderman costume on the morning of September 12, 2014.
Since William's disappearance, investigators have examined hundreds of persons of interest, investigated sightings and seized thousands of pieces of evidence. Source: AAP
Multiple neighbours on Tuesday said they saw the "hysterical" man running around, screaming the child's name.
"I'm sure if William had been around, he would have come to him," neighbour Sharelle Crabb told the inquest.
Her husband, Peter Crabb, said he "looked in places where a little boy might hide" including driving to a nearby swimming pool but there was "nothing, absolutely nothing".
"They (the foster parents) were shouting and screaming off their heads for William," Mr Crabb said, noting numerous others were "coming out of the woodwork" to help.
His wife added: "They both looked extremely distressed."
The foster father of missing three-year-old boy William Tyrrell will be the first witness called on day three of a NSW inquest into his disappearance in 2014. Source: AAP
The couple both heard a car on Benaroon Drive that Friday before they were told about the missing boy, which they say did a U-turn before it drove off but sounded exactly like the postman.
William's foster mother has already testified that she saw three "old" vehicles on the dead-end street that morning including two parked cars which she didn't realise until after William went missing were nowhere to be seen.
Counsel assisting the coroner, Gerard Craddock SC, on Monday said he expected the evidence would establish William "was taken".
