What jurors in Greg Lynn's trial over the deaths of two Victorian ...

For weeks, they sat through evidence in the most high-profile murder case Victoria has seen in recent years.

The jury in the missing campers trial heard from people in Victoria's High Country, family members of Carol Clay and Russell Hill, a range of police scientists, tech experts — and of course, the accused man Greg Lynn.

Finally, they delivered their verdicts, finding Lynn guilty of murdering Ms Clay but not guilty of the murder of Mr Hill.

But there was plenty the jury wasn't able to hear – from secret recordings, to police blunders and an extravagant plan to put the jury in a military helicopter.

Prosecutors were almost forced to drop murder charges against Greg Lynn

Justice Michael Croucher delivered a ruling that could have torpedoed the prosecution case weeks before the start of the missing campers trial.

In early 2024, the judge ruled prosecutors would not be allowed to argue to the jury that Lynn's "incriminating conduct" pointed to an act of murder.

The incriminating conduct included the alleged second killing at the campsite, and the massive cover-up to hide and dispose of Mr Hill and Ms Clay's bodies. 

Carol Clay and Russell Hill disappeared while on a camping trip in Victoria's High Country.(Supplied: Victoria Police)

Instead, the judge said, prosecutors could only use the incriminating conduct evidence to prove Lynn committed an unlawful killing, such as manslaughter.

Given prosecutors had no eyewitnesses to the fatal campsite struggle or conclusive forensic evidence, they wanted to argue Lynn's actions afterwards were so "next level" it proved he committed murder.

Then-lead prosecutor John Dickie said Justice Croucher's ruling meant "the prosecution couldn't proceed in relation to the two charges of murder".

It left the Crown with two options. Drop the murder charges and pursue Lynn for manslaughter, or challenge Justice Croucher's ruling in The Court of Appeal.

"The grounds of appeal will be essentially that Your Honour was wrong," Mr Dickie said.

Weeks later, the Court of Appeal sided with the prosecution, putting their case back on track and setting the stage for Lynn's murder trial.

The secret recordings of Greg and Melanie Lynn

Justice Croucher did not permit prosecutors to play secret recordings of Lynn, which were taken from devices planted in his Caroline Springs home and his Nissan Patrol four-wheel drive.

The judge called the material irrelevant and said it posed a "danger of unfair prejudice by rank speculation".

The jury was shown footage of Greg Lynn walking away from his Point Cook home with an awning he had removed from his vehicle.(Supplied: Supreme Court of Victoria)

During the trial, the jury saw Lynn take the stand and give evidence in a calm and coherent manner.

However, the secret recordings painted him in a different light.

About eight months after the fatal conflict, he was alone in his car and muttering to himself.

From hours of transcripts, separate snippets of his musings emerged in pre-trial hearings:

"Let's see if the cops turn up. If they do, we know they can put a tracker on it."

"F***ing white people. That's all it is. Who can we annoy now? Who can we annoy?"

"Who decides what's right and what's wrong? That's the thing, judgment, judge does, the law does, the community does."

"Ballistics, you'd think they would want samples of my ammo…"

In May 2021, after hearing a radio news story about Mr Hill and Ms Clay, Lynn was recorded saying:

"They're sitting on a beach in f***ing Queensland. Nudist Beach. Butt naked. Playing on his f***ing drone. Running up and down the beach. Taking pictures of the young people. Who's got the biggest dick?"

About a week before Lynn's arrest in late November 2021, he was at home with his wife Melanie when they watched a 60 Minutes program about the missing campers.

It contained a photograph of a mystery vehicle and an artist's impression of it.

This sketch of a vehicle was shown in the 60 minutes program watched by Greg Lynn and his wife.(Supplied: 60 Minutes)

An audio recording captured Ms Lynn bursting into high-pitched, hysterical laughter.

"It looks like your car … it really does!" she exclaimed.

"It's not funny, sweetpea," Lynn replied.

Prosecutors wanted to play the recording to show the jury further evidence of Lynn's cover-up, but Justice Croucher ruled it out.

"She's cackling like a hyena, it might be said," the judge remarked.

Ms Lynn, who was sitting in the court's public gallery as the recording was played, began sobbing as she heard her voice echoing through the room.

Police recorded Greg Lynn and his wife Melanie talking about the then-missing campers as they watched a TV report. (AAP: Diego Fedele)

In an earlier ruling, Justice Croucher said Ms Lynn was also captured saying other things on the recording during the 60 Minutes story.

"Mrs Lynn joked about Mr Lynn having to hide things, how Mrs Clay did not like camping, and how she got 'donked' on her head after someone got mad with her," the judge wrote.

Greg Lynn later told police he had kept the campers' deaths a secret from his wife, and that she had no knowledge of his involvement before his arrest.

The 'oppressive' police interview

On July 14, 2020, two police officers went to Lynn's house to question him about his whereabouts at the time Mr Hill and Ms Clay went missing.

The interaction was secretly recorded by Detective Senior Constable Abbey Justin.

"We're from the police. How are ya?" her colleague Brett Florence asked Lynn.

"Oh, very good," he replied.

"Yeah, mate, you're not in any strife or anything … we're doing an investigation into the missing old couple up in the Wonnangatta area," Sergeant Florence continued.

Detective Senior Constable Abbey Justin was among the officers who interviewed Greg Lynn after the campers' disappearance.(AAP: Diego Fedele)

Lynn then invited the officers into his house, and according to prosecutors, told several lies about his movements in the Wonnangatta Valley.

That evidence never made it to the jury, because Justice Croucher ruled it had been obtained illegally by the officers.

While police claimed Lynn was just a "person of interest" at that stage, the judge ruled that on the balance of probabilities, the officers considered him a homicide suspect and should have informed him of his rights.

Justice Croucher accused police of trying to deceive Lynn at his home and said investigators also made "misleading notes" about his status as a "person of interest".

"This practice must stop," Justice Croucher said. "While honest mistakes will occur, police notes must be as accurate as they reasonably can be, and, above all, they must be intended to be truthful."

About 16 months after police visited Lynn's house, he was arrested.

One of the officers present was Sergeant Florence, who interviewed Lynn with his colleague Daniel Passingham at the Sale police station where the temperature was "freezing".

Lynn told the officers he would be making a "no comment" interview.

He maintained that stance for three days, but the detectives refused to take no for an answer.

Detective Sergeant Brett Florence's conduct during the missing campers investigation came under scrutiny in court.(ABC News: Patrick Rocca)

Their conduct during nine hours of interviews, spread across four days, was described by the judge as a "withering barrage of oppressive and improper inducements".

Pushed to breaking point, Lynn eventually cracked and made confessions about covering up the couple's death, shifting their bodies and his attempts to destroy the remains.

Justice Croucher said Lynn's female lawyer was not present but had told him over the phone not to say anything.

"I wouldn't say she's the expert," Detective Florence said of the lawyer. "It'd be like a flight attendant telling the captain something."

In another exchange, Detective Florence said: "[s]how me why I should be saying to you, 'Greg Lynn, see ya, mate. Here's your keys and I'm really, really sorry'".

Tired of hearing Lynn's "no comment" answers, Leading Senior Constable Passingham retorted: "You might as well just tell lies."

Leading Senior Constable Passingham sought to further induce Lynn, saying: "Our word to the court is favourable."

The jury was shown only part of Greg Lynn's interview with police at Sale Police Station.(Facebook)

After three-and-a-half days, Lynn wilted.

"So in the interests of the inevitable and just getting it resolved now, I'm going to ignore my solicitor's advice and tell you what happened right from the start," he said.

Justice Croucher initially ruled the entire police interview inadmissible because answers had been provided under duress. It was later decided the jury would only see the portion of the interview where Lynn cooperated with police and told them his side of the story.

Last year, Justice Croucher said Victoria Police had not committed to taking disciplinary action against the officers.

Leading Senior Constable Passingham has since resigned from the force.

'I'm just showing you how to ask the questions'

While the trial ran for five weeks, there were dozens of pre-trial hearings in the lead-up and other legal discussions when the jury was out of the room.

Most of the time, conversations and arguments were professional and cordial. Occasionally, jokes or obscure references would be made to musicians or professional athletes.

"Should Jake Fraser-McGurk have been in the Australian Twenty20 team?" Justice Croucher pondered. "I just reckon he's so talented."

However after the trial's 21st day, Justice Croucher was in no laughing mood as he took prosecutor Daniel Porceddu to task over rule breaches committed during the Crown's closing arguments.

In essence, Mr Porceddu made certain claims to the jury about Greg Lynn, which were not put to the accused man during his evidence.

"If you're going to make an argument to the jury about something he said or did, you've got to put that to him for his response. That's the basic rule," the judge said to Mr Porceddu.

The judge said it looked as if Mr Porceddu had "chickened out" during parts of Lynn's cross-examination.

But Mr Porceddu insisted the allegations had been inferred.

When discussing one allegation against Lynn, however, the judge used language for which he later apologised.

Earlier in the day, Mr Porceddu told the jury Lynn had embellished a story told to him by Russell Hill, in a bid to make it appear that Mr Hill was emotionally unstable because he was grieving the death of a relative.

The relative was accidentally shot dead by a hunter in 1994. But the prosecutor said Lynn pretended he was told that the death occurred recently.

"He's going to change the story slightly to make it a little bit more raw?" Justice Croucher asked.

"That's the argument," Mr Porceddu said.

"That's just frog shit, really," the judge replied.

Later, Justice Croucher took Mr Porceddu to other allegations that he said should have been put directly to Lynn.

"I'm just showing you how to ask the questions," the judge said.

At the end of the hearing, the judge apologised to Mr Porceddu for his language.

"I shouldn't have sworn before. I did. And I apologise," he said.   

Plans for a High Country chopper trip

Weeks before the trial started, the Office of Public Prosecutions changed its lead Crown prosecutor for the case.

Mr Porceddu, who runs ultra-marathons in his spare time, was brought in to replace John Dickie.

And with Mr Porceddu came some novel ideas.

Daniel Porceddu led the arguments for the prosecution during the weeks-long murder trial in the Supreme Court.(ABC News: Patrick Rocca)

One was a plan to take the jury, judge and lawyers on a trip to Bucks Camp, where the fatal conflict occurred. They would then travel to the site where the bodies were dumped at Union Spur Track.

Given the distance from Melbourne, the difficult terrain, and a desire to complete the excursion in one day, Mr Porceddu said the best mode of transport would be via helicopter.

But not just any helicopter — an Australian Defence Force Chinook.

"One doesn't understand the vastness of this area unless one sets foot on it," he said.

Justice Croucher had some questions. How long would the chopper ride take? Could everyone fit on board? Who would commandeer the aircraft?

The plan to borrow a Chinook helicopter from the armed forces never eventuated.(Supplied: Australian Army)

Lynn's barrister Dermot Dann KC rose to his feet.

"I take it Mr Lynn is not required to fly the plane," he said, drawing laughter from many inside the courtroom.

The one-liner even brought a wry grin to Lynn's face.

With the OPP (and therefore taxpayers) set to foot the bill, the helicopter plan was abandoned due to the logistical costs.

The ABC understands the estimated cost of the one-day excursion would have run into hundreds of thousands of dollars.

Ultimately, the jury had to settle on viewing crime scene videos on their iPads and large screens in the courtroom.