During the Chris Dawson murder trial, his twin brother Paul staunchly defended him, Lynette's heartbroken family begged for answers, and his second wife was accused of wanting revenge.
Possible sightings of the missing mother-of-two were recounted, there were claims of bruising on Lyn's throat, and allegations of a hitman for hire – but these were all dismissed.
Justice Ian Harrison spent nearly five hours outlining in meticulous detail the reason for his decision, picking apart the last 40 years.
Ultimately the judge ruled Dawson murdered Lyn in January 1982 so he could pursue a relationship with the teenage family babysitter, JC.
Here is how the murder trial unfolded:
READ MORE: Chris Dawson found guilty of murdering his first wife Lynette in 1982
The teenage babysitter
Ultimately, much of Justice Harrison's decision hinged on the testimony of JC, the Dawson family's babysitter.
Just a teenager in the 1980s, she was a student at Cromer High School on Sydney's Northern Beaches, where Dawson worked at the time.
During the trial she testified Dawson once drove her to Western Sydney and told her he was hiring a hitman to kill Lyn.
Justice Harrison declared this "one of the most contentious" claims in the trial and ruled it unlikely but said JC's testimony was otherwise "truthful and reliable".
The judge also said her evidence was "not corrupted" by her separation from Dawson.
JC would go onto be Dawson's second wife, after he moved her into the family home days after Lyn's murder.
During the trial she shed light on what was going through her head as she stood next to Dawson on their wedding day, wearing a ring made from his first wife's engagement and eternity bands.
"Oh my god, what am I doing here… I think I resigned myself that I was not going to get away from him… I don't feel as though I had a choice", she said.
JC also claimed she was instructed to move into the house because Lyn "wasn't coming home", and Dawson needed help looking after the children he shared with his first wife.
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The twin brother
Chris Dawson's twin Paul testified from a police station in Tweed in northern NSW, and described his brother as the "least violent man he's ever met".
A secret phone tap from 1999, recorded after Paul had been grilled by detectives over Lyn's disappearance, was played to the Supreme Court.
In it, Paul suggested Chris' second wife, JC, would be the one with any sort of motive to kill Lyn.
"He (the detective) implied that something has happened to Lyn and that you had the motive," Paul said in the phone call.
"They think something has happened to Lyn and I had the motive and they are going to search the property and do sorts of things. Oh well, good luck to them," Chris replied.
"If anyone had the motive, (JC) had more motive," Paul said.
The dogged detectives
Damian Loone handled the Chris Dawson investigation for nearly two decades.
After taking over the case in 1998, he read transcripts of an old police interview with Chris Dawson and immediately suspected something grave had happened to Lyn, who had vanished 16 years earlier.
During the trial Loone admitted he approached it from a homicide from the beginning, and conceded he failed to take statements from critical witnesses.
These include Lyn's mother Helena Simms and others from the Northbridge Baths who said they remembered Dawson receiving a phone call, which he claimed was his wife saying she needed a few days away.
Loone also acknowledged nothing was formalised after talking to Bayview residents Peter and Jillian Breeze, who reported seeing the missing nurse at Rock Castle Hospital in 1984, two years after she had disappeared.
However yesterday Justice Harrison ruled the baths phone call "a lie" and dismissed any sightings – saying Lyn was murdered on or around January 8, 1982.
Also called to give evidence was John Pendergast, a police officer on Sydney's Northern Beaches for more than three decades before his retirement.
In the late 1990s he offered his help in a renewed appeal in the Lyn Dawson case, but was accused of tunnel vision and ignoring evidence that supported her husband's account.
Pendergast visited Chris' twin Paul and tapped their phones, which he admitted was in the hope of finding something incriminating.
The defence argued the police relied too heavily on JC's story, to which the now-retired detective sergeant said: "She did have a motive, but there's no evidence to suggest at all she was involved in Lynette Dawson's disappearance."
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Lynette's childcare colleagues
Sue Strath never gave up on Lyn.
On the day she was called to give evidence at the murder trial she said: "I am here to see justice done… so let's hope that happens."
The pair worked together at a childcare centre inside the Warriewood shops on Sydney's Northern Beaches on what would be Lyn's last shift before she disappeared in January 1982.
Strath said Lyn confided in her about issues at home, including the troubled teenage babysitter moving in and being caught naked in the backyard pool.
She also claimed Lyn told her about Dawson leaving the family over Christmas in 1981 before reappearing a few days later.
Strath told the court she believed things had turned around after seeing the couple walk hand-in-hand following marriage counselling.
"'I asked how did it go?' and Lyn said, 'Oh it was really good, really positive and I am hoping we can move forward and work together'," Strath told the court in May.
The day after this conversation, Dawson alleges Lyn ran away.
Three years after Lyn vanished, Strath said she lodged a formal complaint with the NSW Ombudsman as she was concerned police had failed to investigate what she thought to be suspicious circumstances.
"I was never interviewed, no one ever came looking for her," Strath said outside court.
"I just said what's happened, what have the police done to look for my friend?"
Annette Leary also worked with Lyn at Warriewood Children's Centre in the 1980s, and said they would have "snippets" of conversations throughout their shifts.
She told the NSW Supreme Court she once asked her colleague about bruises on her throat after Lyn and Chris had attended counselling together.
"She said that Chris had grabbed her throat and shook her a little and said 'if this doesn't work, I'm getting rid of you … I am only doing it once'," Leary said.
Justice Harrison said this incident was "unreliable" and it was "unlikely" bruises would have formed that quickly.
The court also heard from centre director Barbara Cruise, who said Chris had called her to say "Lyn had gone away, she needed some time out and he didn't know when she was coming back".
Cruise told the judge she had doubts about whether Lyn had disappeared of her own free will and once searched for Lyn's mother's name in the phone book, before calling her to raise her concerns.
Phone calls a 'lie'
Justice Ian Harrison said Chris Dawson's claim he received a phone call from Lyn at the Northbridge Baths on January 9, 1982 is "a lie".
"The only evidence that Mr Dawson received a call from Lyn is from Mr Dawson," he said.
"No one apart from Mr Dawson has ever received a phone call from Lyn Dawson since she was last spoken to on Friday January 8, 1982."
Justice Harrison said within the context of an emotional and stressful marriage breakdown he "cannot accept that Lynette Dawson would merely have telephoned Mr Dawson to say that she needed more time".
He said it is "fanciful" in his view to suggest such conversations "lacking in detail" ever occurred.
"It seems remarkable that a woman that was troubled enough to call… Did not feel the need to inform her husband when her final decision was reached."
Justice Harrison said it was concerning to him that Lyn never contacted anybody else besides Dawson.
Possible sightings dismissed
Supposed sightings of Lyn at a bus stop, during a royal visit and a hospital were all ruled false by Justice Harrison.
In a 2019 police interview, Dawson's brother-in-law Ross Hutcheon claimed he saw Lyn waiting for a bus opposite Gladesville Hospital around six months after she went missing.
Hutcheon died in early 2022 before he could testify, so his interview was played at the trial.
"She looked just like the Lyn I knew… same colour hair, same hairstyle, no sunglasses, no obvious attempt to disguise herself or anything like that," Hutcheon told the detectives.
Hutcheon said he told his wife about the possible sighting that same night and two officers later in 1999 but notes from the meeting show no record of that information.
"No mention of Gladesville?" Hutcheon asked the officer after reading the police notes.
The police officer responded: "No."
"Wrong, wrong," Hutcheon said.
"Are you certain you told them about it?" the police officer asked Hutcheon.
"Certain, that is wrong," Hutcheon responded as he handed back the papers.
The sighting was raised again in 2018 after Dawson was charged with murder.
Dawson's sister, whose name is also Lynette, was grilled by the prosecutor about why she didn't discuss the sighting with her family for 36 years.
She told the judge she always assumed her sister-in-law had upped and left and never imagined it would be treated as a murder.
An elderly family friend Elva McBay claimed she saw Lyn run across the road in front of Prince Charles an Diana's motorcade in 1983.
Neighbours Peter and Jillian Breese testified they saw a woman who looked like Lyn working at Rockcastle Hospital two years after she vanished.
None of the reported sightings were ever confirmed, some were properly investigated, and all turned out to be impossible.
The hit podcast
It's impossible to tell the story of the Dawson murder trial without mentioning The Teacher's Pet, a hit podcast by The Australian Newspaper.
The show's creator – journalist Hedley Thomas – was called as a witness and defended accusations he led a campaign against Dawson, but conceded he did think he was guilty of murdering his wife.
"I thought he was likely to have, but I still had an open mind about it. I wanted to learn more about it. I became more sure as time went on," Thomas told the Supreme Court.
The award-winning 16-episode series was released in 2018 and has since been downloaded 60 million times across the globe.
The same year the podcast took off, detectives from NSW Police announced a dig at the Dawson couple's former home in Bayview on Sydney's Northern Beaches.
The veteran reporter rejected suggestions he was out to condemn Dawson.
"I had a view about him, which I felt was very suspicious and the view strengthened as I read more and spoke to more people," Thomas said.
