After three days of arguments, a panel of judges will consider whether to overturn an allegedly "unreasonable" verdict finding Chris Dawson murdered his wife more than 40 years ago.
The NSW Court of Criminal Appeal has heard submissions from the ex-teacher's barrister Belinda Rigg SC as to why the August 2022 verdict should be quashed.
On Wednesday, she restated her claim there was not enough evidence to show beyond reasonable doubt Lynette Dawson was not alive on January 9, 1982 and her husband was guilty of her murder.
In 2022, Supreme Court Justice Ian Harrison found Dawson killed his wife and disposed of her body around that time so he could have unfettered access to a teenage girl who was one of his students.
Ms Rigg has argued the judge impermissibly used the 75-year-old's claimed lies as showing consciousness of guilt, and failed to take into account the significant disadvantage faced in defending a four-decade-old murder charge.
Earlier on Wednesday, crown prosecutor Brett Hatfield SC acknowledged Justice Harrison's reasoning had its issues, particularly regarding lies and a consciousness of guilt.
"We can't get away from the fact that the language (of the judgment) is problematic," he said.
However, he said a finding of guilt should still follow from the finding Dawson had lied about receiving a phone call from his wife on January 9, 1982.
The ex-teacher claims Ms Dawson told him on that call and in later phone conversations she wanted time alone to think things over.
At the time, Dawson had pursued the teenage student, who can legally only be referred to as JC, sending her love letters and sleeping with her in his family home in Sydney's northern beaches.
Justice Harrison found Ms Dawson was dead by January 9 and her husband had lied about the call.
"Once you've found beyond reasonable doubt that he's lying about the call on that day ... there was only one outcome that could follow," Mr Hatfield told a three-judge panel on Wednesday.
Dawson's version of what happened - that his wife completely abandoned her home, children, family and friends because of his infidelity - was glaringly improbable, the prosecutor said.
The ex-teacher's various claims of where his wife was, including at a Blue Mountains commune and in New Zealand, were designed to be "vague, unverifiable and unlikely to attract suspicion in his direction", Mr Hatfield said.
Claimed sightings by others of Ms Dawson alive after January 9 were also inherently problematic and weak, he added.
"Do you say the strength of the crown case irrespective of what the trial judge did was so great it reduced the defence case to a fanciful hypothesis?" Justice Christine Adamson asked.
"Yes, we do say that," Mr Hatfield replied.
Justices Julie Ward, Anthony Payne and Christine Adamson will deliver their decision at a later date.
If Dawson is successful on his appeal, he could be acquitted or have a retrial.
