A red dog, two horses and a set of teeth.

Key points: In the drought of 1938, three men went missing: a labourer, a gold prospector and a pensioner

In the drought of 1938, three men went missing: a labourer, a gold prospector and a pensioner They had set out for work near Narromine in western NSW but never made it home

They had set out for work near Narromine in western NSW but never made it home Albert Andrew Moss was sentenced for the murder of one of the men, but claimed to have killed 13 people

That's all the evidence police had to pin Albert Andrew Moss for a triple murder.

'Mad Mossy', whose grim crimes took place 80 years ago, said he killed 13 victims but new research casts doubt on his infamous claims.

"If he did get a baker's dozen it would make him one of Australia's most prolific serial killers," said historian Jessica Moore.

"But he always overstated his boldness, his terror, his violence."

Deep waterholes dynamited in search for bodies

In the summer of December 1938, three men went missing.

It was a drought year, and crops in western New South Wales had failed, forcing hundreds of people to hit the road in search of jobs, food and a bed.

Labourer William Henry Bartley, gold prospector Timothy O'Shea and pensioner Thomas Robinson all set out for work near Narromine but never made it home.

"These were men living on the fringes of our community but when these sorts of people didn't show up for a job alarms went off," said Ms Moore, whose research on 'Mad Mossy' is being exhibited at the Western Plains Cultural Centre in Dubbo.

Thomas Robinson's red kelpie was found in Moss's possession at the time of his arrest. ( Supplied: State Archives of New South Wales )

Bartley disappeared on December 1 and the authorities quickly turned their attention to Moss after he was spotted riding the missing man's bicycle.

Soon after, Moss was seen driving a sulky pulled by two horses. They belonged to O'Shea.

By January, the career criminal had upgraded his mode of transport again: this time he was pulling Robinson's sulky. And what's worse, he was found in possession of Robinson's dog.

"It's a very dramatic story as Moss was a very dramatic character," she said.

In April 1939, the tale of the missing men made national news after police detonated sticks of dynamite along the banks of the Macquarie River near Narromine.

Police were searching the river bed for the missing men, having found human teeth and bone fragments in a nearby campfire.

These horses belonging to Timothy O'Shea were in Moss's possession. ( Supplied: State Archives of New South Wales )

'A baker's dozen': Could it be true?

Moss, pictured here aged 24, lived a life of crime. ( Supplied: State Library of New South Wales )

For 80 years, Australian tabloids have been gripped by the tale of 'Mad Mossy', with public intrigue fuelled by salacious headlines like 'The fiend who slew a baker's dozen'.

Now, after a year-long research expedition, Ms Moore has found the hype around the so-called 'homicidal hobo' claim to be false.

"Moss was pathological liar," she said.

"He routinely lied about things that made him tougher, braver, bolder."

Her research showed his lies included fighting in World War One, taking a trip to America, having illegitimate children and relocating his family to New Zealand.

"He didn't just tell small lies. He would spin grand tales that we, as researchers, could easily prove weren't true."

Could police have missed something?

In Dubbo Supreme Court in September 1939, Moss was tried for the murder of O'Shea. It was the first murder trial in New South Wales to take place without a corpse.

Ms Moore's research shows police exhausted all possible resources to convict him.

"Various records showed the police force in Dubbo almost tripled in size during the search for Moss's victims," she said.

"There were references to police travelling close to 20,000 miles across the state to investigate every possible reported sighting of the missing men."

If the police had found evidence to link him to other missing persons cases, she said, they would have followed it.

This photo shows where Moss camped with Robinson before he disappeared. ( Supplied )

What about the others?

In the post-depression years, thousands of Australians packed up their homes and set off in search of a better life.

But despite the increased social mobility of the era, Ms Moore found the population density of western New South Wales was low enough that any missing person would raise suspicion.

During the era that Moss killed his victims, she found no evidence of a spate of disappearances.

"I don't believe Moss killed the extra 10 people he said he did because we just don't have the evidence that this number of people were missing from society. If they were, it would have been a sensation in the newspapers."

Did he feign insanity?

Moss spent significant periods of his life in mental health care in Sydney and Orange. ( Supplied: State Library of New South Wales )

Forensic psychiatrist Dr Robert Kaplan from the University of Wollongong said it was unusual for serial killers to inflate the number of victims and when they do it was often an attempt to feign insanity.

"It's called governor's pleasure. It's all about getting reductions to prison time on psychiatric grounds," he said.

"This isn't something serial killers do often."

Ms Moore's research shows Moss spent significant periods of his life in mental healthcare facilities in Orange and Sydney.

The historian learned on one occasion, when led to a crime scene by police, Moss hopped like a kangaroo, put grass and thistles in his mouth and flapped his arms like a crow.

But when it came to his murder trial, doctors told the court he wasn't insane.

"There was a real sense of Moss being a shadowy figure and a real bogeyman and that reputation still exists after all these years," Ms Moore said.

Moss was sentenced to death by hanging for the murder of O'Shea. The Crown did not continue with proceedings for the murders of Robinson and Bartley.

He died in Long Bay Penitentiary hospital on January 24, 1958.