An inquest into the disappearance of William Tyrrell looks likely after deputy state coroner Harriet Grahame joined police searching for new forensic evidence, as they attempt to unravel the 2014 mystery.
NSW Police Detective Chief Inspector Gary Jubelin and the deputy coroner spent most of Tuesday at the former home of William's foster grandmother before driving into nearby bush.
About 30 police officers, Rural Fire Service and State Emergency Services crews spent the past four weeks combing bushland near the Kendall property where the three-year-old vanished in September 2014.
Detectives believe William was abducted, with the latest search, which began in June, geared towards proving William disappeared because of human intervention and not misadventure.
If an inquest is announced, police will have to table almost four years of evidence, while any persons of interest could be called upon to face a public hearing overseen by the deputy coroner.
Ms Grahame would have to make a ruling on one of Australia's most enduring missing person cases, which has cast a dark shadow over the sleepy town, south-west of Port Macquarie.
Information about a "high-risk" person of interest spurred the hunt for William Tyrrell into new territory at Batar Creek, coinciding with the boy's seventh birthday.
Police spent two days canvasing 800 square metres of bushland, before returning to Kendall, where the month-long search will conclude at the end of this week.
Inspector Jubelin said investigators gained new information from the search, but failed to reach the breakthrough they had been hoping for.
Police looked at almost 700 persons of interest, conducted hundreds of interviews and gathered more than 4,000 pieces of evidence, but Williams' disappearance remains a mystery.
