'We could hear the guns' - the psychiatrist who lived near Aramoana and became a leading expert on lone mass killers

When 14 people were killed not far from his family home in the Aramoana massacre, Dr Paul E Mullen was working at Otago University.

Six years later, he'd become a professor of forensic psychiatry at Melbourne's Monash University and was asked to examine the 23-year-old man who just hours before had killed 35 people in the Tasmanian town of Port Arthur.

Mullen tells RNZ's Sunday Morning that he was doing his job, trying to establish some conversational rapport with the young man, when suddenly a little grin appeared on his face: "He said, 'I've got the record, haven't I?' He had killed more people than any lone gunman before him."

Like many such killers Mullen has spoken to, there was a moment when things could have gone another way for the Tasmanian gunman, the 81-year-old says.

"In many of the cases, right up to the last moment, many of these killers are really unsure… Uncertainty up until almost the last minute is something which I have heard from more than one of these killers."

The fact that the Port Arthur murderer stopped for a cup of coffee on his way to carry out the shooting reveals he was "in two minds", Mullen says.

"This man was plagued throughout his adult life by looking handsome, looking bright and intelligent, and being totally incapable of a reasonable social interaction, which wasn't awkward and clumsy and usually intrusive and rude.

"He's sitting in the cafe. There's a couple of young women there, and he decides he'd give the world a second chance, maybe for once, he won't be rejected.

"He made his usual approach, and he was his usual intrusive, rude self, although his appearance promised something rather better. And he got his usual response, and they simply moved away. If they hadn't, he says he wouldn't have gone ahead."

In his new book Running Amok: Inside the Mind of the Lone Mass Killer, Mullen explores a phenomenon which is said to have begun in 1966 when a 25-year-old male University of Texas student opened fire from an observation deck, killing 15 people and injuring another 30.

That perpetrator was one of the over 80 percent of American lone mass killers who die among their victims, Mullen says, but in Australia and New Zealand, it's quite the reverse and 80 percent survive.

"They do not get the death they're seeking, and they are likely to finish up being humiliated in front of a court."

As a result of so many Australasian lone killers surviving, Mullen has been able to interview many of them.

He says the men who commit these crimes - there have been no documented women - are all deeply resentful about what they view as severe mistreatment.

"That emotion comes back to haunt you and comes to be your way of seeing the world. In other words, the world is humiliating you, insulting you, treating you unjustly and you're just taking it. You're not fighting back. You have failed."

While these people may be isolated, they're usually "on the internet the whole time", Mullen says, and develop political views around their resentment and a fascination with guns.

These potential killers almost always let people know of their intentions in advance, he says - in conversation, via internet posts or in school essays or university essays - and can sometimes be diverted from their path of destruction.

"Most of the ones we see who issued these kinds of threats, there is no chance that they were going to act on them. They wanted to make a fuss. They wanted a bit of attention… Most of them have never really faced up to the reality of what they're planning to do. It's all fantasy."

Disturbingly, those who do go through with mass killings very rarely have a history of violence, Mullen says.

"They are not people who go around confronting others or standing up for themselves or getting into any kind of violent crime. These are the frightened of the Earth, really."

To help counteract the development of resentment in these men's hearts, our culture must emerge from outdated "notions of male superiority and female inferiority", Mullen says.

"Many men can't really cope with even the small changes which have occurred so far. We've got a long way to go, but things are changing."

When someone mentions committing a massacre, or there's any reason to think they might, the first "simple, straightforward" action is to make sure they don't have access to guns, Mullen says.

Then, ideally, the person can be engaged in some kind of therapeutic relationship to help them try and deal with their problems.

What the killers he has studied all desire, and should not be granted, he says, is fame.

"They want their names alongside people they see as heroes. If we can at least make clear to people who are contemplating this, one thing you are not going to get is name recognition and fame; you will be forgotten."

The media have to report tragedies and victims deserve to be remembered, Mullen says, but what is not deserved is a killer getting the personal notoriety they crave.

The Christchurch mosque shooter, for example, received a vast amount of publicity for killing 51 people and injuring 89 in March 2019, but was ultimately deprived of this wish, Mullen says.

"In the end, he finishes up as a powerless prisoner, living out his days in obscurity as he should."