One of Australia's longest-running cold cases documented in the popular “Teacher's Pet” podcast has ended with the conviction of Chris Dawson for the murder of his wife Lynette.

Dawson, 74, was arrested in 2018 after police re-examined evidence and investigated new claims made in the podcast that the high school teacher was having an affair with a 16-year-old student when his wife vanished in January 1982.

Dawson has long denied any involvement in the disappearance of his wife, who was 33 when her husband formally reported her missing in February of the same year.

He claimed she walked out on him and their two young children, and pleaded not guilty to one charge of murder.

On Tuesday, Justice Ian Harrison discounted sightings of her in subsequent years as mistaken or fabricated, and said while the verdict was unsupported by direct evidence, circumstantial evidence pointed to Dawson's guilt.

“The whole of the circumstantial evidence satisfies me that Lynette Dawson is dead, that she died on or about 8 January 1982, and that she did not voluntarily abandon her home,” Harrison said.

“I'm satisfied beyond reasonable doubt that the only rational inference that the circumstances enable me to draw is that Lynette Dawson died or on about 8 January 1982 as the result of a conscious and voluntary act committed by Mr. Dawson with the intention of causing her death.”

'Lynette Dawson is dead'

The Dawsons had known each other since they were teenagers and later married and had two children. Dawson had long maintained that his wife had abandoned the family, and that he had spoken to her in the weeks after her disappearance.

Those claims were dismissed by the judge, who said it “defies common sense” that a woman “supposedly desperate to leave her marriage” would phone him to provide updates on the "status of her decision to leave.”

“I'm satisfied beyond unreasonable doubt that Mr. Dawson's reported telephone conversations with Lynette Dawson after January 1982 are lies,” Harrison said.

Harrison also found that claims Lynette Dawson used her credit card soon after her disappearance were fabricated and that sightings of her in later years were mistaken or false.

“I'm satisfied that none of the alleged sightings was a genuine sighting of Lynette Dawson,” Harrison said.

The Crown submitted evidence of exhaustive searches involving interviews and public records that showed Dawson hadn't used her passport or accessed the health, tax or any other Australian public system since 1982.

He said he also reached that conclusion based on the fact that no one had come forward with information regarding her disappearance despite intense publicity over the case, including the “Teacher's Pet” podcast, coronial inquests in 2001 and 2003, and several television programs.

Police searched the Dawsons' former Bayview home again in 2018.

Evidence from babysitter

The judge recapped the relationship between Dawson and JC, his former student who later became his wife.

The court heard she was a student in his physical education class at Cromer High School in Sydney. By the time she left school, they were in a sexual relationship and he had become infatuated with her, the court heard.

Harrison said he found evidence from JC to be “truthful and reliable.”

The court heard JC family life was difficult; she lived at home with a “violent, aggressive and controlling” stepfather in a cramped apartment where there was excessive drinking. She had turned to her teacher for support and guidance, Harrison said.

“(JC) was understandably attracted to any relief she could obtain from a less than perfect domestic situation,” Harrison said in the ruling.

In 1980, JC started babysitting for the Dawson family, the court heard. Dawson was also giving her driving lessons, and one day while they were in the car, he professed his love and kissed her.

They had sex about one week later, when she was 16 years old.

After that, they would regularly have sex in his car, Harrison said, recounting JC testimony.

On these occasions, Dawson would tell his wife he was studying at the library.

The same year, the violence at JC home had become intolerable and she moved into the Dawson family's house. JC said Dawson would sing “cruel songs” to his wife, and they would have sex when Lynette was in the shower or had fallen asleep.

The Crown alleged Dawson was obsessed with JC and within days of his wife's disappearance on January 8 he drove his former student back to his house. The Crown's case contended that he was “not prepared to waste any time before installing her in his home.”

Harrison said: “By the time the relationship became a sexual relationship, Mr. Dawson was becoming confronted with the stark reality that he could not remain married, yet still maintain his ever more intense relationship with (JC).”

Escaping to a new life

Harrison delivered his verdict over several hours on Tuesday, offering detailed analysis of evidence submitted by multiple witnesses during the three-month long trial.

Harrison pointed out that a number of witnesses had died during the decades between Lynette's disappearance and the start of the trial in May. However, he said examination of those witnesses' testimony suggests their evidence was not crucial to its outcome.

Harrison said he wasn't convinced Dawson was violent toward Lynette Dawson, but there was no question the marriage was in trouble. “The circumstances point persuasively to a conclusion that Mr. Dawson decided that he would end his marriage and move on with Joanne,” Harrison said.

The marriage between JC and Dawson ended in 1991, and Dawson disputed some of her evidence as the words of an aggrieved ex-wife. Harrison found JC had become swept up in a situation over which she had little control.

JC gave evidence of Dawson's controlling behavior, saying he monitored the places she went, the friends she made and the clothes she wore.

That obsession with JC was enough to motivate him to kill Lynette, Harrison found.

It's still unclear what happened to Lynette Dawson.

Harrison said evidence did not reveal how Dawson killed her, whether he did it with the assistance others or by himself.

“It does not reveal where or when he did so, nor does it reveal where Lynette Dawson's body is now. The charge of murder in this trial is unsupported by direct evidence,” he said.

Yet, he said he found the evidence presented by the Crown to be” and compelling.”

The judge ordered Dawson, who was sitting in court to hear the verdict, to be taken into custody. (CNN)

*This story has been updated

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