The news headline told of cold-blooded murder, but the face staring back at me was that of my childhood friend.

I woke up on December 13, 2022, and scanned the news headlines in bed.

A story had captured international attention. Two police and a neighbour had been murdered on a remote property at Wieambilla, three hours west of Brisbane. Their three killers died in a shootout with police.

When I clicked on the story, I saw a face I recognised instantly. Fair skin, freckles and red hair. Time froze. Then memories came flooding back.

The more I learned from the newsroom, the more surreal it became.

The killers were two brothers and the older brother’s wife. They ambushed police, executing a constable as she lay pleading for her life. The property was set up for armed assaults on intruders, with sniper hideouts, CCTV and an escape hatch in the house.

Police deemed them religious extremists who believed officers were demons coming for them at the “end of days” before Jesus returned to the earth.

But to me, they were my childhood friend and his family.

Nathaniel had been in my home. I’d expected to see him one day playing the Davis Cup or Wimbledon — not as Australia’s first Christian terrorist.

For 20 months since, I’ve brooded over the question: how did my gifted, well-adjusted friend become an infamous killer?

Early glimpses of Christian ideals

This is me at 12.

And that’s Nathaniel.

This was our class photo at Eagle Junction State School in 1988. It was in Clayfield, a dress circle suburb of Brisbane — kids of doctors and lawyers with big houses.

David Norris remembers being “in awe” of Nathaniel, the new kid in town — and one of the best tennis players in Queensland for his age. “He was an extremely talented sportsman.”

Robert Tam remembers a “very well-behaved … normal kid”.

“Maybe a little bit too nice, in the sense that he went through all the motions of wrapping a present, giving a card, going for the conventions, if you like.”

James Rossiter remembers going to Clayfield Baptist Church, where Nathaniel’s dad was a student pastor, and the Train family lived. He recalls it as the kind of place where “it is drummed into you [that] the world is a wicked place … full of evil and full of, I guess, traps”.

“And unless you stick by the code or the morals … of the ‘good book’ … you’ll be heading in the wrong direction … you are doomed … you’re ‘not one of us’.”

At my 12th birthday sleepover, Nathaniel showed us a glimpse of his conservative Christian values.

When someone pulled out one of my big brother’s dirty magazines, everyone gawked and laughed, except Nathaniel, who said: “That’s disgusting.”

Still, he was happy to join us as we rented horror movies and snuck out to rock people’s roofs at night for thrills.

“Being the little 12-year-old bastards that we were at the time … I remember him sort of tagging along with our stupid activities,” says another mate, Andrew Burge.

The origins of brothers’ deadly bond

We all lost touch with Nathaniel after primary school.

His family moved to regional Queensland where his father took appointments as a Baptist minister, settling in the bible belt of Toowoomba.

Ron Train was a postal worker who became a born-again Christian in 1980 and sold the family home to enter bible college.

He remembers discussing theology with Nathaniel, a “studier of the scriptures and very black and white [in interpretation] — not much grey for Nathaniel”.

Nathaniel was one of four children, but closest to his brother Gareth, who was a year older.

Ron says Gareth was “more aggressive, controlling” with a “short fuse” and a problem with authority.

Gareth had learning difficulties and his mother later suspected undiagnosed autism spectrum disorder.

“If Gareth flew off the handle, Nathaniel would be there to quieten and talk to him and help him to work through issues.”

As a student at an agricultural college at Dalby, Gareth was expelled for putting a bully through plate glass.

The brothers learned to handle guns as teenagers, hunting and skinning kangaroos.

But Gareth’s interest in weapons went beyond those used for hunting.

He once asked his father to move a pistol hidden in the roof of the family home, after being detained by police on a buffalo hunting trip with friends.

After high school, Nathaniel and Gareth both applied to join the army.

Ron says Nathaniel was earmarked as officer material, but Gareth “failed the psych test”.

Nathaniel opted out in solidarity, and studied to become a physical education teacher instead.

By then, Nathaniel had given up on his tennis dreams, despite spending his mid-teens hovering around Queensland’s top four for his age.

At around 15, he’d asked his parents if they had $1 million, because that’s what his coach said it would take to get him to Wimbledon.

“I said, ‘No, son, I’m sorry. We can’t help you there’,” Ron says.

I wondered if that crushed Nathaniel — to have his dream snatched away because he wasn’t a rich kid.

But Ron says his son was stoic by nature.

And he found a new love which eclipsed tennis.

The woman he’d live and die with

“It wasn’t long after that he met Stacey,” Ron says.

“She distracted him from his tennis. [But] you can’t deny young love. So we just realised that.”

Stacey Christoffel and her family were members of the Toowoomba Baptist church where Ron Train was minister.

She was beautiful and clever, and raised with a “similar belief system” which “would have attracted Nathaniel”, Ron says.

Stacey was also prone to “obsessive-compulsive” behaviour, according to Ron, with Nathaniel a “calming influence”.

She was happy to challenge Ron as her pastor, telling him in Church one day, “I don’t believe a word you said today”.

Stacey got an OP1, the top academic score in high school.

But it seemed “her ambition was to be married and to have children with Nathaniel”, Ron says.

They got engaged in 1995 when Stacey was working in the law office of future Queensland attorney-general Kerry Shine.

Stacey’s parents, who’d left the church, weren’t happy with the engagement and asked her to leave home.

Ron says his decision to marry the couple in his church “didn’t go down well with Stacey’s parents” either.

When the couple signed their wedding certificate, Gareth looked on as best man.

The allegations that bonded the trio

Eight members of the cash-strapped Train family, including Nathaniel, Stacey and Gareth, pooled resources to buy a property near Toowoomba.

Soon, Nathaniel and Stacey had a daughter, Madelyn, and a son, Aidan, on the way.

Then straight out of university, Nathaniel was headhunted to teach at a high school with an elite sports program at Kooralbyn, near the Gold Coast.

Meanwhile, Stacey had made a discovery that “deeply troubled” her, Ron says.