A massive brief of evidence, containing at least 15,000 items, will go before Deputy State Coroner Harriet Grahame at the launch of the inquest this morning.
But, according to The Sun Herald and the Sunday Age, the inquest will focus on a new person of interest — a man who has never been publicly discussed by detectives.
Throughout the investigation, William was referred to "a little boy lost" but police soon came to suspect something more sinister happened and zeroed in on known paedophiles and criminals from nearby holiday towns.
But no one has been charged for the suspected abduction.
AAP understands investigators hope the first week of hearings will show William did not wander into nearby bushland but was, instead, snatched by a predator.
In mid-2018 they conducted a large-scale search of bushland near the Kendall home to rule out misadventure and firm up their theory.
The closely-guarded persons of interest list, which ballooned to include hundreds of names over the years, has been whittled down for the inquest's second sitting in August.
Some names on that list have been previously released by police but sources say one so-far unidentified person will be watched closely when they are called in front of the inquest.
