Image copyright SUPPLIED Image caption Lynette Dawson, a mother of two, was last seen in 1982

On paper it was an old story, told many times over the years.

In the early 1980s, Sydney housewife and mother-of-two Lynette Dawson suddenly disappeared. Over the next 30 years, police searched fruitlessly for her.

But now, exactly 37 years after her husband Chris Dawson said he last saw her, investigators may finally be closer to finding out the truth.

Last month, police finally made an arrest in the case: Lynette's husband. He has always denied any involvement.

It is hard to say exactly what prompted this latest development, but more than a few people have pointed towards a podcast released in May 2018.

The Australian's series The Teacher's Pet - which reinvestigated the case in huge detail and uncovered new witnesses and evidence - caught the attention of millions of people around the globe.

As yet, it is unclear exactly what role, if any, the podcast played. After all, police had been conducting their own reinvestigation for the past three years.

However, many have been left wondering: if not for the work done by journalist Hedley Thomas and his team, would they have jumped into action so quickly?

'We're not law enforcement'

It is not the first time it's been suggested that a wildly-successful podcast has had an impact on the justice system.

Years before The Teacher's Pet became a must-hear, Serial was essential listening. It focused on the conviction of Adnan Syed, who was jailed for the murder of his ex-girlfriend Hae Min Lee back in 2000, and ended with a retrial being ordered.

In 2018, it was the turn of another US podcast, In the Dark, to raise questions about a murder conviction. The show's second season told the story of Curtis Flowers, a black Mississippi man tried six times for the same crime by the same white prosecutor.

That a man could be tried six times for the same crime seems shocking in itself, but more shocking still were the allegations of racial bias, and shifting witness statements - which kept listeners hooked.

Image copyright In The Dark Image caption Curtis Flowers has been in prison since 1997

The US Supreme Court is now due to hear Flowers' sixth appeal. If that fails, his lawyers will take the case back to the Mississippi Supreme Court - this time aided by the podcast's discoveries.

However, In the Dark's Madeleine Baran says she and her team were not - and had never been - "trying to solve the crime".

"We are not law enforcement," she stresses.

It may be for just that reason that podcasts do manage to turn up evidence - or pull apart what were once believed to be cast-iron truths - missed by officials.

"We have an advantage in that we're not the prosecutor and we are not the defence," Baran says. "That is really important - you need to be calm with factors going either way."

You also, of course, need to tell a good story - good enough to capture the attention of everyone from truck drivers to joggers.

Last hope

There was no suggestion Police Scotland had done anything wrong in its investigation into the murder of Alistair Wilson, the father-of-two shot dead on his doorstep in the sleepy seaside town of Nairn 13 years ago.

But the fact it remained unsolved so many years later caught the attention of BBC journalist Fiona Walker, the reporter behind last year's hit podcast The Doorstep Murder.

"I think everybody wants the crime to be solved, but after 13 years people had lost faith in the official process," she explained.

"They felt our investigations unit was a way of taking another serious look at it."

Image copyright PA Image caption The mystery of why Alistair Wilson, pictured with his wife Veronica, was killed remains unsolved

Baran recognises this loss of trust in the authorities: she certainly saw it in Mississippi.

"The people talking to us had been really treated poorly by the whole process," she said. "They did not want to talk. They were not easy to get to talk."

In fact, Baran and her team would spend a year living in the town, building trust, returning over and over to speak to people, teasing out their recollections.

For Walker, a tip-off from a source who did not trust the police was the opening she needed to get started on her own investigation.

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"The source had this breadth of information and he needed to off-load it," she said. "He had knowledge, a social conscience. But at the same time, he was genuinely scared for his life."

This access to people who might otherwise not speak to officials connected with the case can give these podcasts an edge.

"People have felt they can come forward to me who are not coming forward to the police," Walker acknowledges. "It is easier to approach me. I've invited them to approach me."

But both journalists point to other factors as well: time, and a determination to leave no stone unturned.

Image copyright Ben Depp for APM Reports Image caption Curtis Flowers' parents Archie and Lola spoke at length to Baran and her team

For Walker, that meant having patience during "months and months" of little to no movement as she waited for people to decide to talk.

For Baran, it meant re-treading old ground, pushing every contact, and - at one point - digging through piles of prison booking-in cards in an abandoned plastic factory on the off-chance it might contain the one piece of information she was missing.

It was only later, looking at photos, they discovered they had hit the jackpot.

"We realised one of these cards was this name that we have been trying to find for a year - among all these mouse droppings."

Of course, there are pitfalls too: the potential for a so-called "trial by media", as thousands of armchair detectives try to work out exactly whodunit, is not insignificant. Could the information the podcast puts out potentially end up prejudicing or damaging a future trial?

Turning the tide

And yet, even the police have cottoned onto the medium as a way solve crimes.

In California, Newport Police Department's Jennifer Manzella hit on the idea as a way to help them track down Peter Chadwick - a millionaire property developer they allege killed his wife back in 2012. He skipped bail in January 2015.

Mr Chadwick presented Newport PD with a relatively unique problem, in that his wealth meant "he has the resources to be anywhere in the world", Manzella explained.

Image copyright Newport Police Department Image caption Peter Chadwick (left) allegedly killed his wife Quee Choo in 2014, before fleeing on bail

So getting the story out far and wide was imperative - and there was only one medium Manzella could think of with the power to do just that: a podcast.

And it worked. The afternoon Newport PD unveiled Countdown to Capture, there were "dozens" of tips. More followed, and continue to drip in even now, months later.

"We could never have anticipated the amount of interest. They came forward in their droves," Manzella says.

"We have gone years without getting any tips. We had done national television appeals and got no tips, or maybe one."

It has given everyone hope - not least his wife's family.

"He is living in somebody's community somewhere," Manzella told the BBC. "We just need people to tell us."

Her words are almost echoed by Det Supt Gary Cunningham, the man leading the investigation into Alistair Wilson's death back in Scotland: "Someone out there knows why Alistair Wilson was killed and who was involved in his murder."

Neither Newport PD nor the BBC's podcasts have helped solve the case - yet. There is still the chance they may prove key.

"The podcast is not fleeting: it is continuing to reach new people and at any point there might be that one person with the information to solve it," Walker points out.

But that also means any further developments will also be scrutinised closely by millions who now feel they have a stake in the story - and there is nothing like the expectation of millions to focus the mind.