Detectives investigating the disappearance of three-year-old NSW boy William Tyrrell have narrowed the focus of their seven-year probe to a single suspect.
Police Commissioner Mick Fuller says there has been a significant breakthrough in the case and he's confident police will solve the mystery.
"There is certainly one person in particular that we are looking closely at," he told Sydney radio 2GB on Tuesday.
"I certainly don't want to declare too much because again in these cases you do not want to compromise a potential outcome.
"Officers have been working tirelessly to get to this point where we are searching land, again using the best technology available."
NSW Police announced on Monday they were conducting a new "high intensity" search for William's remains near the Kendall home. Source: SBS / , NSW Police
The case of the missing boy in the Spider-Man suit has captured the nation's attention since William disappeared from the garden of his foster grandmother's Kendall home on the NSW mid-north coast in 2014.
On Monday, NSW Police announced they were conducting a new "high intensity" search for William's remains near the Kendall home. Police are being assisted in the search by 30 SES volunteers.
Vision of the search area on Tuesday showed the volunteers using chainsaws and other heavy-duty equipment to clear dense bushland, including felling big trees.
Asked about reports police were seeking an apprehended violence order against a person or persons of interest in the case, Police Minister David Elliott was also reticent to say too much.
"It is a matter of public record that police are issuing AVOs," he told the Seven Network.
"We need to be cautious about how we discuss that in the public domain so smart lawyers don't use our comments to neutralise a conviction."
Earlier, he told the Nine Network it was "a matter of public record that a number of people who had relationships with William have been questioned by police".
William's foster family have never been publicly named due to legal reasons.
Ten reporter Lia Harris, who interviewed the foster parents for her 2019 podcast 'Where's William Tyrrell' said she had recently received a subpoena from the coroner's court for "a very broad range of material".
"Everything that I had uncovered in my research for the podcast, audio files, documents, everything, including those raw tapes of my extensive interviews with the foster parents," she told 2GB on Tuesday
"To me, it signalled that they had either taken a new direction or they had a new theory they were working on."
The findings of a coronial inquest into William's disappearance, which concluded last year, are yet to be handed down.
A $1 million reward for information on the case still stands.