The 28-year-old Tasmanian named Martin Bryant had killed 35 people, including a mother and her two daughters aged 3 and 6 years old. Photo / 60 Minutes

Australians woke up 25 years ago to the news of a violent rampage in a remote part of Tasmania.

It was Monday, April 29, 1996 and we had just become the location of the world's worst massacre perpetrated by a lone gunman.

A 28-year-old Tasmanian named Martin Bryant had killed 35 people, including a mother and her two daughters aged 3 and 6 years old.

Starting at lunchtime the day before, Bryant had carved a path of destruction through Port Arthur on Tasmania's southeast coast.

The historic tourist site, and in particular its Broad Arrow cafe, held painful memories of rejection for Bryant, a social misfit with a pathetic need for revenge and notoriety.

Taking a Colt AR-15 .223 semiautomatic rifle, an SLR semiautomatic .308 rifle, a semiautomatic Daewoo 12-gauge shotgun and 150,000 rounds of ammunition, Bryant mercilessly slaughtered anyone he could shoot.

He told one man, who miraculously survived being shot in the neck, "No-one gets away from me".

In his mind, Bryant might have been acting out his favourite movie character, the evil doll-come-to-life Chucky from Child's Play.

Around 8am on the Monday, after an 18-hour stand-off with police, Bryant ran from the Seascape Cottage where he had killed three people and was captured by police.

He has been in custody ever since.

But even before he pleaded guilty to 35 counts of murder and was sentenced to life in November, 1996, the conspiracy theories had begun to surface.

People with supposed special knowledge of what really went on issued all sorts of claims.

"Bryant had an IQ of 65, he wasn't bright enough to plan and carry out a massacre," one such theory goes. "He couldn't have done it because he couldn't shoot and he didn't really have those weapons."

"There was no hard evidence to prove he was even there," others claim.

"Forces were at work. It was a government plot to have guns outlawed," according to others.

"The Tasmanian Government had bought a 22-body refrigerated mortuary truck specially made in readiness."

They go on and on.

"Apart from tourists, the Broad Arrow cafe was crammed with a contingent of police, military and intelligence.

"Covert ASIO handlers were in the car park.

"The people shot in the cafe included government agents who were killed to prevent them for revealing the plot.

"Officials who thereafter handled the case were corrupt.

"An innocent mentally handicapped 'boy-man' has been wrongfully put in jail for LIFE."

In the mid-90s the internet was relatively young, so at first the conspiracy theories proliferated in booklets and magazines, such as Deadly Deception by Joe Vialls and Nexus magazine's Martin Bryant Framed.

Googling those three words today throws up numerous pages with rants about Bryant's supposed innocence, his cruel injustice and "ongoing torture" by the Tasmanian Government.

And these are not just remnants of something imagined long ago.

There's a great number of Port Arthur conspiracy theorists around today, as witnessed when news.com.au published an article about Bryant a month ago.

The story set down Bryant's bizarre life, from shooting birds with an air rifle, to taking potshots at Port Arthur tourists, being a nuisance at its cafe and violent obsessions into adulthood.

The conspiracists were enraged.

One wrote, in fury, "Your (sic) so full off s**t still spreading your media poison.

"I know the real truth about what happened from people that were there, the truth that will never be told or ever see the light of day."

Another, whose name I'll omit in favour of his initials, MB, wrote, half intelligibly:

"It was the government %100… maybe if you look into mk ultra program run by milabs or monarch or even kruger."

The conspiracy theorists also offer up thoughts on who they claim was really behind the shootings. A popular theory being that it was carried out by US and Israeli military personnel to trigger a national disdain for guns.

Others claim a "one-world government" wanted to take out guns and were in cahoots with John Howard.

Within 12 days of the tragedy, the then prime minister introduced laws restricting ownership of semiautomatic weapons and pump-action shotguns.

Some of those behind the Port Arthur conspiracies became party members of One Nation when Pauline Hanson launched it in 1997.

Hanson alluded to the conspiracies during the 2019 US National Rifle Association set-up, when she was unaware she was being filmed by Al Jazeera.

On the tape, broadcast on the ABC, Hanson spoke with undercover reporter Rodger Muller, who was posing as a gun campaigner.

"An MP said it would actually take a massacre in Tasmania to change the gun laws in Australia," Hanson told Muller.

"Haven't you heard that? Have a look at it. It was said on the floor of parliament.

"Those shots, those were precision shots. Check the number out.

"I've read a lot and I have read the book on it, Port Arthur. A lot of questions there."

Hanson later backtracked, saying she had been "stitched up" by a "hit piece" that had been "heavily edited".

She said: "There is no question in my mind that Martin Bryant was the only person responsible for the murders of 35 innocent lives."

Walter Mikac, the father and husband of the three victims shot near the Port Arthur toll booth, Nanette, 36, Alannah, 6, and Madeline Mikac, 3, was said to be devastated by Hanson's words.

Doubtless other family members of the those Bryant murdered, and those who managed to escape, would be hurt by the conspiracy theorists.

Why Bryant was the only gunman at Port Arthur

The conspiracists say that for starters, only a trained marksman could have killed all those people and Bryant was not one.

They claim it would be particularly difficult given his severe form of Asperger's syndrome and low IQ.

That's not true.

On the ground in Port Arthur the day after the massacre, news.com.au was told by people who knew Bryant that he was a fairly good shot.

After checking into the Port Arthur Motor Inn, I was told by a staff member how she and others called Bryant "silly Martin, no sense no feelings" for his paucity of conscience or social skills.

She described how he shot birds and other animals and then continued to pump rounds into their bodies and brains.

It was even easier to murder human beings at Port Arthur, trapped inside the Broad Arrow cafe and gift shop by a man with a semiautomatic weapon at point-blank range.

The others he shot in a tourist coach, in a car and at close range.

His principal weapon, an AR-15 is the type of assault rifle used in mass killings in America, a lethal weapon in the hands of losers and misfits like Bryant.

It was used at Sandy Hook, the Dark Knight movie theatre, the Colorado theatre, and the Parkland, Florida school.

In the last decade, 21 mass shootings in America have been carried out with Bryant's weapon of choice.

It is the firearm used by people who want to wreak maximum havoc with an enormous amount of killing power and, chillingly, "maximum wound effect".

And no-one claims Bryant shot with precision.

When he didn't have his victims trapped at close range his wayward bullets hit trees, vehicles and the ground.

In his ghastly, giggling post-massacre police interview, Bryant refers to his AR-15 as "a sweet little gun".

Conspiracy theorists claim to know better than the rest of us.

They claim to know what "really happened" and say master manipulators are controlling us blind fools.

Desperate to establish "there is no proof" that Bryant is the Port Arthur mass murderer, they fail to provide any evidence for their laughably paranoid fantasies.