A coronial inquest into the disappearance of a 12-year-old boy from the West Australian town of Derby almost 40 years ago has heard police did not believe foul play was involved.

James 'Jimmy' Patrick Taylor was last seen buying a soft drink from a local shop in the Kimberley town on 29 August, 1974.

His body was never found and no-one was charged over his disappearance.

The three-day inquest before coroner Barry Paul King is investigating a possible link between his disappearance and convicted child killer Leigh Anthony Bridgart.

Bridgart changed his name to James Ryan O'Neill when he left Victoria in the 1970s.

Jimmy was not reported missing by his father until seven days after his disappearance, as it was thought the boy had accompanied his friend to a family station.

In the opening address, the court heard today there was no thought of foul play by police who originally investigated the disappearance.

The court heard police presumed the boy had run away from an unhappy home environment and an alcoholic father who sometimes beat family members.

After several unconfirmed sightings across the Kimberley, Derby police advised the Taylor family in 1979 there were no further inquiries that could be made.

Documentary leads to case being re-opened

However in 2006, the Taylor family watched a documentary on the ABC titled The fishermen: A journey into the mind of a killer.

It featured O'Neill who is is serving a life sentence in Tasmania for abducting and murdering a nine-year-old boy.

The documentary alleged Bridgart was residing in or near Derby in 1974 under the name of James Ryan O'Neill.

Jimmy's sister Lyn Henderson-Yates requested the special crime squad re-open the case.

Detective Senior Sergeant Mark Cunningham, who was part of the review team, told the court that persons of interest included O'Neill.

He said the team investigated a witness report claiming to have seen Jimmy get into an "unknown vehicle driven by an unknown Caucasian male".

The court was told the review Bridgart had made his way to WA in 1971 or 1972 after being charged in relation to several sexual assault allegations against young boys.

He had been working in Fitzroy Crossing where he got married and changed his name to James Ryan O'Neill.

Sergeant Cunningham said Bridgart told his wife the name change was needed due to his work as a former undercover ASIO agent.

The couple eventually moved to Tasmania, the state in which O'Neill was later convicted of the murder of a nine-year-old boy.

Sergeant Cunningham told the court that during an interview Bridgart denied having anything to do with the disappearance of Jimmy Taylor.

The court heard Bridgart told Sergeant Cunningham: "I didn't do it, I know you don't believe me but I didn't do it."

Sergeant Cunningham told the court the review concluded it was "most probable Jimmy Taylor was deceased" and that it was "probable it was a result of abduction and subsequent murder".

He also said the review was hindered by an "'extended passing of time" and the fact that some witnesses either had "difficulty recalling events or had died of old age".

Under cross examination, Mr Cunningham told the court police did not have evidence that placed Bridgart in Derby on the day Jimmy went missing; "We don't know where he was on that date," he said.

Journalist gives evidence at inquest

The journalist who made the documentary, Janine Widgery, also gave evidence in court today.

She told the court she had left a life of crime reporting to make a documentary about unsolved child murders.

Ms Widgery said she had wanted to follow up possible links between O'Neill and the missing Beaumont children, and had got O'Neill to agree to being part of the documentary under the guise of it being about his worm farm within the prison and his trips around Australia.

The court was told a High Court injunction was sought to prevent the documentary from airing, because O'Neill felt he had been defamed, however the documentary was eventually broadcast.

Family endure 'great silence of 40 years' waiting for answers

Jimmy's mother, Evelyn Henderson, told the inquiry "none of her children would ever run away".

She said she just kept thinking "you never know, something might turn up... some new evidence".

Jimmy's sister Heather Winifred Taylor was seven-and-a-half years old when her brother disappeared, but she told the inquest today "that day was significant enough to stay in my mind".

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