Australia’s most notorious mass killer is now so obese he needs three mattresses to sleep and once passed the time bragging to fellow inmates about a pen pal ‘girlfriend’, it can be revealed.

Martin Bryant is known for the shooting murders of 35 people at the Tasmanian historic site Port Arthur on April 28, 1996 – now age 58, he’s “lower than zero” on the pecking order at Risdon Prison Complex and is bullied over his former chocolate-fuelled sexcapades with other prisoners.

His face is ravaged with acne and he barely speaks to anyone, save the occasional game of chess.

A News Corp investigation has uncovered fresh details about Bryant and the massacre that shocked Australia, including unearthed psychiatric reports written just hours after the bloodshed almost three decades ago.

Exclusive vision shows a limping Bryant dressed in prison blacks lining up with his fellow prisoners against a steel fence, holding a white mug, during a headcount in the Mersey Unit’s exercise yard.

Jackson*, 50, decided to ask Bryant about the Port Arthur massacre during a game of chess inside the Mersey Unit for inmates struggling with mental illness, when they were cell neighbours.

Over 10 days, Jackson slowly won Bryant’s trust with packets of sugar from breakfast.

“He’s probably not what you’d expect before you meet him … you think he’s going be a 66 IQ (his official score) … but he’s actually a lot smarter than that,” Jackson said.

“He doesn’t come across like what you’d think. If you didn’t know what he did, you’d just think he’s a quiet bloke trying to do his time … he’s not like a day-to-day psychopath.”

Bryant had superficial interactions with guards and other inmates, but Jackson said he was the only person inside the 15-person unit who attempted to talk to him properly.

When Jackson finally worked up the courage to ask about Port Arthur, he said Bryant’s face fell.

“It certainly hits him when you ask the question,” he said.

“Embarrassment is not the right word. You can see there’s something there.”

WATCH EXCLUSIVE VIDEO OF AUSTRALIA’S WORST SERIAL KILLER:

Jackson was in cell 11 and Bryant was in cell nine, his sheer size requiring three mattresses.

Wardens rouse prisoners at 7.15am every day, but Bryant rarely leaves his cell in the morning.

“Every morning, you could hear him yell out, ‘Can you turn the lights out in cell number nine please,” Jackson said.

In the morning, prisoners receive a meal pack with a plastic bag of cereal, seven packets of sugar, three packets of international roast, and a packet of jam.

Every second day, inmates are given a 300ml milk container and meals are trolleyed into the unit throughout the day.

Wardens summon inmates for a headcount several times a day. Aside from a few board games and the exercise yard, there’s not a lot to do inside the Mersey Unit.

“It’s boring as hell, there’s not much excitement,” Jackson said.

He grew close to Bryant over his 15-day stint at the unit, and said the mass killer once even grabbed his phone to say hello to his mother. Both men have mothers called Carleen, though the spelling is different.

Jackson said Bryant interacts with other prisoners and guards but there were no meaningful relationships.

He described Bryant as having two sides: the drugged up idiot bullied by other prisoners for past sexual acts, and the man who played chess and fondly reminisced about past travels.

“He acts like a bit of a dope,” says Jackson.

“He’s had a few sexual experiences in jail so someone will tease him and go ‘How about you swap me a head job for a Mars Bar with such and such’.

“He’ll go ‘Ha yeah’, then you can actually talk to him about his travels around the world. You can talk to him about his favourite restaurants in Germany. He’s articulate. You can play chess against him and he’s not just reactive, he’s proactive and thinks moves ahead.”

Jackson also said Bryant was not big on personal hygiene, describing him as “pretty slovenly”.

“His face is full of acne, he has dry skin, flaky dry skin,” he said. “He could certainly do with a facial.”

Jackson didn’t know whether Bryant’s mother still visits him in jail, but he did say the killer claimed to be in a long distance relationship with a woman from a property in Victoria.

“He talked about her quite often,” Jackson said.

“He bragged about having a girlfriend, apparently she had a horse property in Victoria. I believe he even showed me a photo of her at one stage.

“I’m not sure how the relationship started but I think it had been going on for a number of years, it wasn’t a fresh thing.

“I’m not sure she had ever visited. I just know it was letters and phone calls. You’re only allowed 10 people to call, so she would have been approved by the prison service to call him.”

Bryant never mentioned Tattersalls heiress Helen Harvey, who left a young and pre-murderous Bryant with the fortune that funded his trips overseas – and the arsenal used at Port Arthur.

Jackson said Bryant received special attention inside Risdon and that guards went out of their way to protect him from other prisoners.

“If there’s any trouble to do with Martin, whoever’s causing the problem, they’re what they called Shanghai’d [removed],” he said.

“Because they don’t really have anywhere else for [him] to go.”

Bryant’s atrocities were carried out using an AR-15 semiautomatic rifle.

It remains one of the most traumatic events to take place on Australian soil and triggered a rapid overhaul of the nation’s gun laws under then-Prime Minister John Howard.

For nearly three decades, the wounds of Port Arthur have been dressed with silence, a mark of respect to the direct victims and a nation struggling to process an unbearable tragedy.

The pain left by that single day still haunts Tasmania and much of the nation, an overwhelming grief as deep as the dark waters that surround Hobart.

Many Tasmanians have a connection to the tragic events that unfolded at Port Arthur and knew either one of the victims, or Bryant himself.

NSW upper house member Jeremy Buckingham recalled hearing an emergency radio broadcast about a shooting at Port Arthur while at a fish and chip shop in Sorell.

“My brother and I were travelling down but we were overtaken by police cars, military vehicles, and then we got to a place called Taranna,” he says.

“We got there and they say that they’re not letting anyone in other than residents.”

Mr Buckingham, a member of the Legalise Cannabis Party, said Bryant was well known around Hobart for being a gun nut who collected pornography, crashed parties and harassed women.

“I remember him turning up at a party in Newbeena and he was talking about weapons and guns and that stuff,” he says.

“We were hippies and surfers, laid back and no one was really into that … And it’s easy to say that he genuinely had a strange manner and vibe, he put people on edge.

“The bottom line was no one was that surprised, he was a ticking time bomb for a long time.”

Bryant’s desperate parents took him to a number of psychologists in an effort to diagnose their son but no illness captured the child’s violent outbursts and anti-social behaviour.

Lawyer John Avery represented Bryant during his sentencing, the then 28-year-old pleading guilty at the behest of his mother.

Mr Avery says his main preoccupation during Bryant’s brief court appearances in 1996 was making sure his client behaved.

“The actual day that occurred was more keeping him in line because he always wanted to be the centre of attention – whether it was going to proceed to a trial or, as it did, proceed to a plea of guilty,” he says.

“I don’t have any doubt in recalling that event, it was pretty historical.”

Mr Avery says the time had come to start talking about Port Arthur and that the enduring lesson of the tragedy was gun control.

“I think the time has come where it can’t be hidden and his name no longer mentioned and that sort of thing,” he says.

“I think that the time has come for it to be put in historical context and no longer refusing to talk about it.”

Former Risdon guard Tony Burley said Bryant is lower than zero on the prison food chain and often stared intensely at the prison officers.

“It was creepy. Creepy, like crazy,” he said.

“But nothing to be scared or worried about, just, yeah. I’d look and think, ‘what the f*** are you looking at, you idiot? Look somewhere else.”

Mr Burley said he doesn’t understand the fascination with Bryant who he described as being “thick as two short planks”.

“You’ve got some prisoners down in Tasmania who could break out of a bloody coffin, and he’s just a waste of oxygen really,” he said.

“In terms of the food chain, he’s lower than zero. It’s not that people don’t like him, he just doesn’t exist. No one would know who he was, he’s not a concern to anybody, he’s not targeted, he’s nobody.”

Do you have a story? Email charlotte.karp@news.com.au