As the mother of missing toddler William Tyrrell walked in circles and ripped open cupboards yelling, "You need to talk to mummy and tell me where you are," she knew in the pit of her stomach that someone had snatched him.

Her horrifying account of the moment her son vanished comes as police investigate information which may link an organised paedophile ring to the three-year-old's abduction.

"When I realised that William was missing – I think back to that moment where I just went, 'I can't hear him, why, why can't I hear him'," she said.

"I just walked out and just I see nothing, I hear nothing, I'm speechless.  I'm walking around in a circle on the spot thinking where is he? Why can't I see him? And I'm yelling out, 'William, where are you'?

"I kept going in my head, 'somebody has taken him'. In my mind it was the only logical explanation for what could have happened."

William was playing with his sister in the yard of his grandmother's Kendall home when he vanished on September 12 last year.

Police say they received information in the past few weeks which has led them to home in on a local paedophile ring which operates close to where the toddler disappeared.

The head of the homicide investigation, Detective Inspector Gary Jubelin, said the information was new, solid and that he believed a number of people in the ring may have played a role in William's abduction.

"We've uncovered and received information that leads us to a line of people we suspect of being involved in paedophile activity," Detective Inspector Jubelin said.

"We are exploring information linking them to William's disappearance," he said.

William's parents, who cannot be named for legal reasons, spoke about the stomach-churning day their little boy disappeared wearing his favourite Spider-Man outfit. They say there is no way he would ever wander off. 

The family travelled from Sydney to visit William's grandmother in Kendall and described William's joy at having a rare meal at McDonald's on the road trip.

Just moments before he was abducted, his mother snapped a photo of him drawing a picture with crayons. He wanted to place his artwork on his grandfather's grave after his recent death.

"I look at that picture and I just think minutes [later] and our world has changed, his sister no longer has a brother, we no longer have a child, we no longer have a boy," she said.

"It's the never-ending nightmare, we wake up, we just re-live it. I just can't believe it's happened. We just don't have our boy, we have no idea where he is, we don't know who's got him ... we just want it to be over."

William's father said he struggles not to cry when he looks at the last photo taken of his "cheeky, vibrant little boy".

He said he always felt his little boy had been stolen as he searched with hundreds of volunteers and police in nearby Kendall State Forest and MIddle Brother State Forest for days. 

"As I was walking through the bush with other people it became more aware to me that this is not a child gone missing in the bush … this is heading down the path of abduction," he said.

In January, police seized a number of items from the Bonny Hills home and Laurieton office of whitegood repairman Bill Spedding who was due to fix a washing machine at William's grandmother's house close to the time the toddler went missing.

He has denied any involvement and police have repeatedly said he was not a suspect but "a person on interest".

In March police spent three days searching dense bushland in Queens Lake Conservation Area about 21 kilometres from Kendall and conducted a number of searches since. 

Although police fear the worst for William, his parents hold onto the faint hope that he is alive.