Police have been ordered to produce transcripts of more than 500 hours of recordings from a listening device planted in the home of Kathleen Folbigg.
The second inquiry into Kathleen Folbigg's convictions for killing her four children has adjourned until April after police tabled, at the last minute, recordings from a device that was planted in Folbigg's Hunter Valley home in 1999.
Folbigg stood trial and was convicted of three counts of murder and one of manslaughter in 2003 and it is not yet confirmed if the tapes are relevant to the latest inquiry into her convictions.
Retired chief justice Tom Bathurst, KC, who has presided over the two-week judicial inquiry, said he did not want the 55-year-old to have to wait a long time for his report and asked for police to provide transcripts of the tapes as soon as possible.
"It's a matter of concern they were produced so late," he added.
The inquiry heard some of the material may have already been transcribed for the trial in 2003.
The second judicial inquiry was called after the discovery of a rare gene mutation that causes heart problems and sudden death, found in Folbigg's two daughters.
It has seen a clash of expert opinions.
Several witnesses maintain the rare gene mutation may have caused the deaths of Laura and Sarah, but some have ruled it out.
Separate medical conditions have been proposed as a possible cause of the deaths of Caleb and Patrick.
The children died on separate occasions between 1989 and 1999, with no signs of injury, so the Crown case at trial was that Folbigg smothered them, but she has always maintained they died of natural causes.
Peter Fleming, a world-renowned paediatric intensivist, said he helped investigate more than 800 child deaths, and children who are smothered usually have injuries in their mouth caused by them struggling.
He said the Folbigg children did not have these injuries, so he found it hard to accept they had been smothered.
"It is possible but very hard to accept and I'd be very surprised," Professor Fleming said.
Mr Bathurst noted that at a 2019 judicial inquiry, experts claimed "the absence of any signs of smothering supported the hypothesis of smothering".
Professor Fleming responded that he had much more experience in this field of research than the witnesses at the trial and subsequent inquiry.
"A paediatric intensivist was not asked their opinion on this in either the trial or the first inquiry," he said.
"I have greater experience than the others who gave evidence."
Allan Cala, the forensic pathologist who did the post-mortem on Laura and gave evidence at Folbigg's 2003 trial, stood by his view that smothering may leave no injuries at all.
He told the inquiry that Professor Fleming's domain was in hospitals and ICU units, but he had a much better overview of the matter.
Mr Bathurst cancelled the appearance of another witness, Joanna Garstang, a UK-based paediatrician who reviewed Folbigg's diaries and concluded they did not contain "true confessions" of criminal guilt, after lawyers for the Director of Public Prosecutions argued the witness did not have access to a "substantial body of evidence" in forming her view, including the trial evidence.
Diary entries were key to the case against Folbigg in 2003, but forensic psychologist Patrick Sheehan said rather than an admission of guilt, they were about guilt of a different kind.
"To deal with her own badness, or something she's carried on through her terrible childhood … or failings as a mother."
Mr Bathurst will decide if the inquiry evidence raises reasonable doubt about Folbigg's guilt.
If his decision is yes, the case could go back to the Court of Criminal Appeal to consider a pardon or retrial.
Folbigg will either remain in jail to serve out the remaining five years of her 25-year sentence, or walk free, making her story one of the greatest wrongful incarcerations in Australia's history.
