Wieambilla shooting: Stacey Train had limited contact with family after entering ‘controlling’ relationship with brother-in-law

Every year, Stacey Train's mother would call the mobile of her estranged daughter and leave a message on her birthday.

But, according to another family member, if her son-in-law, Gareth, picked up she would quickly hang up.

Stacey's parents are understood to have had limited contact with Stacey for many years, which a relative has put down to Gareth's "controlling" behaviour.

Stacey and Gareth were killed in a firefight with police on Monday, alongside his brother Nathaniel - who was also Stacey's first husband - after they shot and killed two officers and a neighbour.

Speaking to Guardian Australia, a family member of Stacey's remembers a quiet girl who was always somehow the odd one out.

While the family "all grew up in church", Stacey branched off into the independent church of Ronald A Train, her future husbands' father, on her own as a teenager.

"I wish she never did," the relative, who asked to remain anonymous, said. "This would never have happened."

It was there she met Nathaniel Train, who she married. Some time later she left him for Gareth.

"I knew Gareth was an arsehole when he took over his brother's wife," the family member said.

"It was all downhill from there. Now she is dead because of them."

It is a sentiment shared by some in the Queensland town of Camooweal, where the couple once lived. One resident told the ABC that Gareth "was a control freak" and that Stacey "could never say anything", while another said she once saw him assault his wife by dragging her by the hair up a set of stairs.

On Thursday it emerged that the trio had rigged up a "sophisticated surveillance system" at their remote property to help them "take police out", according to the Queensland Police Union's president, Ian Leavers.

"That is very, very concerning to us - knowing that this ruthless, murderous trio went to this extent with a view, I firmly believe, to take police out," Leavers told ABC Radio.

Forensic examinations are continuing at the Wieambilla house, in the Western Downs region, where constables Matthew Arnold and Rachel McCrow and neighbour Alan Dare were gunned down.

On Wednesday, it emerged that Gareth and Nathaniel Train had also become estranged from their father, a conservative Christian pastor, after the breakdown of Nathaniel's marriage to Stacey.

Ronald Train told A Current Affair on Wednesday he hadn't spoken to either man in 23 years.

While appalled by their actions, he said he could not be held responsible, even though he understood why people would be critical of him.

"I'll stand before God for what they've done," he said.

Despite not speaking in more than two decades, the pastor said he had still prayed regularly for his sons.

Stacey's sisters were understood to have been at their parents' home in North Queensland when they heard the news that she had been shot dead.

According to a relative, the family is no closer to understanding how their quiet girl became involved in multiple murders. But they rue the day she ever met the Train family.