Police on Sunday seized a white utility from Bulga, about 78 kilometres from where AJ went missing, as part of their investigations.

They have also set up Strike Force Jaylang to investigate what may have happened to the three-year-old.

As the third day of the search for the three-year-old wrapped up on Sunday, fears were growing that the boy may have been abducted.

AJ's godfather Alan Hashem told Sunrise on Monday that CCTV footage from cameras he installed that overlook the property "went missing" at the time of the disappearance.

"Probably about four hours, there's footage missing," he said.

More than 130 people spent the weekend searching the network of trails, creeks and swamps that make up the family's 650 acre property off Yengo Drive at Putty for any trace of the boy.

They persisted despite the rain that sent temperatures plummeting on Saturday night.

In addition to searching in the bushland, divers also searched and drained a large dam on the property.

AJ, who has non-verbal autism, was last seen playing with his brother when he disappeared just before midday on Friday.

It is believed he was alone for a few minutes before his disappearance.

The family say a "suspicious" white Toyota Hilux dual-cab ute was seen in the vicinity on Friday.

Hunter Valley Police District commander Superintendent Tracy Chapman said police were "absolutely looking into every angle possible in relation to AJ's disappearance."

"We do have an investigation underway and are following up every lead."

In addition to the massive search operation, which includes fixed-wing drones, PolAir, and mounted officers, forensics detectives spent the night collecting evidence from around the property.

AJ's family, who moved to the property just three months ago, said it was out of character for him to wander off.

"I just want to find my son, I need to find AJ," the missing boy's mother Kelly Elfalak told 9News.

"I've searched the property, so many times I've searched and I still cannot find him.

"I'm his universe, he holds my hand all day and all night, we are together all the time - something's not right."

Neighbours believe it is possible AJ may have sought shelter in one of the many wombat holes or caves in the area.

An emergency text message was circulated across the Hunter Region on Saturday appealing for information.

AJ is believed to be wearing a grey jumper, pants and sneakers.

He is described as being of Mediterranean or Middle Eastern appearance with short dark hair.

Anyone with information about this incident is urged to contact Crime Stoppers: 1800 333 000 or https://nsw.crimestoppers.com.au.

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