Tyrell abductor may have watched boy

Detectives haven't ruled out the possibility that the person responsible for abducting toddler William Tyrell loitered outside his grandmother's home before snatching the three-year-old as soon as he was alone.

It's coming up to six months since William disappeared without a trace from his grandmother's NSW home in the quiet mid-north coast community of Kendall, near Port Macquarie.

He'd been playing in the yard on the morning of September 12 when he was last seen going around the side of the home towards a grassy area near the road.

In those few moments when he was out of the sights of his mother and grandmother, he vanished.

Police have ruled out a case of a little boy lost and believe he was abducted.

The highly experienced homicide detective leading the investigation, Detective Inspector Gary Jubelin, labelled the crime "opportunistic".

And he hasn't ruled out the scenario that someone was watching from outside the Kendall home until William was left alone.

"It's a huge coincidence that you have a situation where a young boy has been unsupervised, only for a very short moment, and someone has come into contact with him at the time," he told AAP, noting how quiet the street is.

"There is hardly any traffic and you can stand out there for half an hour to an hour without a car passing by."

Detectives have issued stern advice to anyone who was within a 1km radius of the Kendall home between 10am and 11am, around the time William went missing, to come forward.

As opposed to a normal appeal for public information, anyone who fits the criteria and doesn't come forward will attract police suspicion.

"If they don't come forward to police, we would have some concern and attach a certain amount of suspicion to anyone that doesn't want to help police in an investigation of this nature," Det Insp Jubelin said.

Police hope to recreate the situation in which William disappeared from accounts of everyone who was in the area.

Homicide squad is leading the charge on the case but sex crimes detectives are also involved.

Strike Force Rosann involves 12 full-time detectives working meticulously on the investigation.

As for William's family, they are holding up as best as they can, despite the pain of not knowing.

"I can't speak for the family but I have been doing this for a long time and I am very much aware of the fact that families suffer when they don't know what has happened to their loved ones," Det Insp Jubelin said.

Last month police raided a home, unit and office connected to local washing machine repairman William "Bill" Spedding.

They seized a mattress, computer and vehicles, among other items for forensic testing.

Mr Spedding has denied any involvement and police stress he is not a suspect.

Police wouldn't comment on the result of that line of inquiry.