A former detective in the William Tyrrell case has hit back at suggestions from the NSW Police Commissioner that there was "wasted" time in the early years of the search.
NSW Police Commissioner Mick Fuller took the extraordinary step of blasting the initial search for 3-year-old William, codenamed Strike Force Rosann, on Tuesday.
"The investigation was looking at some persons of interest that were clearly not, and I think some time was wasted on that, and bushland is overgrown," Fuller said in a radio interview.
"But a new team onboard inherited what was a bit of a mess and have cleaned up that investigation."
Detective Gary Jubelin, who ran the Tyrrell case for four years before resigning from the NSW Police Force as a detective inspector in 2019, told the Australian it was "disappointing" that Fuller has decided to criticise the Tyrrell investigation now.
"As the commissioner, he is ultimately responsible for the investigation that has been running the whole time he was commissioner," Jubelin said, adding he was never given any criticism or advice about his handling of the search for William at the time.
"I own and take responsibility for the way I led the investigation," he said. "I hope the police who sat above me are prepared to do the same thing.
"There were a lot of hardworking police on the investigation who were determined to find out what happened to William. I am sure they would not appreciate the public criticism from their commissioner."
Jubelin resigned from the police force over claims he illegally recorded conversations with a person of interest. He lost an appeal against the ruling later that year.
The Australian revealed that NSW Homicide Squad officers have identified a suspect seven years after the little boy went missing.
Police are searching the Kendall home on NSW's north coast belonging to William's foster grandmother, whom William was visiting in 2014 when he went missing.
Police have said they believe the search will uncover William's remains.
In September, police said they had obtained fresh information about William's disappearance.