A hit and run or a murder?

That's the 14-year-old mystery at the heart of a coronial inquest that began in WA's premier tourist town of Broome that has baffled investigators for years.

At its centre, a happy-go-lucky young apprentice whose lifeless body was found by the side of a road in February 2010, and his crusading mother who has never stopped seeking answers about what happened to her son.

Josh Warneke was just 21 when he died, a young carpenter nearing the end of his apprenticeship who should have had his whole life ahead of him.

Witnesses at the inquest have described him as a friendly and outgoing person who loved to go out dancing and socialising at Broome's nightspots.

He was kind, too.

"[He'd] give you the shirt off his back" is how one workmate described him.

Mango madness

By all accounts, Thursday February 25, 2010 was a typical warm night, the unofficial start of the weekend and a good night to hit the town.

Summertime in Broome is wet season.

It's hot and humid and sticky and sweaty, and the town can sometimes feel on edge, waiting for that first big rain to finally provide some brief respite from the seemingly endless heat.

Mango Madness is what some call it, a time when tempers fray and violence seems closer to the surface. Research shows you're more than three times more likely to be assaulted at this time of year if you live in Australia's north.

Thursday nights in Broome in 2010 at this time of the year were especially popular – it was the night the town's biggest and most popular pub, the Roebuck Bay Hotel, held its weekly wet t-shirt competition.

And Josh Warneke and his friends were out to enjoy themselves.

A big night out

Witnesses told how Josh was in good form that night, cheerful and carefree as he visited the town's nightspots.

He'd been at the crowded wet t-shirt competition, which had been packed with backpackers and locals, then at the Bungalow bar nightclub drinking Coronas.

The well-liked young tradie had caught up with many friends and acquaintances throughout the course of the evening.

It was late when he called it a night, sometime after 2am, leaving the nightclub to walk home alone via the local McDonalds, where a taxi driver saw him wandering near the drive-through.

It was the last time anyone saw him alive.

Less than half an hour later, another taxi driver came across a body lying by the road not far from the Roebuck Estate where he lived.

It was Josh.

An arrest for murder

What happened to Josh in the few minutes between when he was last seen to when his body was discovered has been the subject of multiple police investigations and a bungled manslaughter conviction.

Josh died of a head injury. His skull had been fractured and his head covered in bruises and lacerations. But what caused it has never been ascertained.

By 2012 police thought they had cracked the case.

They arrested 18-year-old Gene Gibson, from the remote desert community of Kiwikurra and charged him with murder after he apparently confessed to assaulting Josh in an interview.

Mr Gibson spoke almost no English and was mentally impaired, and the police interviews were ruled inadmissible by a Supreme Court judge and the charge downgraded to manslaughter.

Mr Gibson pleaded guilty and spent nearly five years in prison until his conviction was overturned in 2017, thanks in large part to the efforts of Josh's mum Ingrid Bishop, who'd come to believe he was not responsible for her son's death.

Mr Gibson was ultimately awarded $1.3 million in compensation for his ordeal, and police were hauled over the coals by the Corruption and Crime Commission.

In a scathing report, the CCC found police had failed to follow procedures when interviewing Mr Gibson and had botched the investigation.

Police then launched a cold case review of the case, and offered a $250,000 reward for information, later increased to $1 million. The money has never been claimed.

The suspects and the theories

It's been more than 14 years since Josh died, and his mum still doesn't have the answers she's been seeking about what happened to her son on that warm summer's night.

And now that the coronial inquest into his death has wrapped up after nine days, it's not clear whether she ever will.

Much of the evidence presented has revisited old ground already unearthed during the CCC investigation.

But there have been some new nuggets of information that might help.

We now know that police identified at least 850 potential witnesses during their investigations, of whom between 80 and 90 per cent were interviewed.

At least 15 were considered suspects, albeit not strong suspects.

And there have been more theories advanced about how he died, including that he was struck by a star picket or machete or that he received a glancing blow from a vehicle.

Mr Warneke's body was found in what WA Police Sergeant David Magorian, an expert in crash investigations, described as an "unusual" position, lying perpendicular to the road, half on the bitumen and half on the gravel shoulder.

His thongs were about 30 centimetres from his right foot, positioned at right angles to each other.

Neurosurgery professor Bryant Stokes was of the opinion that a weapon had caused his head injuries, most likely a "sharp instrument" such as a machete or star picket, but other experts disagreed.

Forensic pathologists Clive Cooke and Michael Burke both thought a car was involved, and that his head injuries were likely caused by a glancing blow from a passing vehicle, rather than having been run over.

His level of intoxication may also have been a factor, Dr Cooke said, having recorded a blood alcohol reading of 0.183.

What happens now?

The coronial inquest heard from 30 witnesses in all, including mates who'd been drinking with Josh the night he died, police who had examined the scene and those who'd been involved in various investigations over the years, and taxi drivers.

In an unusual development part-way through the inquest, the legal team representing Ms Bishop asked for it to be adjourned for six months, a request Coroner Ros Fogliani ultimately rejected.

It was Ms Bishop, of course, who fought for so many years to have the inquest held at all.

However, the ABC is unable to reveal the reasons behind the unexpected request for legal reasons.

With the coronial hearings now completed, it's now up to Coroner Fogliani to sift through the sometimes conflicting evidence to try to find out what really happened to Josh.

And no-one wants that more than Ms Bishop.

"This coronial inquest into the death of my son Josh is the culmination of nearly 10 years of advocacy, planning, self-education and resolute determination to achieve two outcomes – how was Josh murdered and what were the circumstances," she told the inquest.

"Every word I say and every action I undertake is with the intent to achieve these outcomes."

The toll it has taken on her seems impossible to overstate.

"Albeit it all-consuming, my resilience is strong and the love for my son fuels my intent.

"I will continue to hold Josh's hand through this horrific and never-ending ordeal until the time comes when I don't need to."