Investigators will track every keystroke of the Train family's dark path toward the deadly Queensland ambush that left six people dead, including two heroic police officers.
Constables Matthew Arnold, 26, and Rachel McCrow, 29, along with 58-year-old resident Alan Dare, were killed in a hail of bullets at a rural property at Wieambulla in the western Darling Downs region on Monday.
Prime Minister Anthony Albanese, who previously said the officers paid a price no one who puts on the uniform should ever pay, will lead tributes to the pair in federal parliament on Thursday.
Constables Randall Kirk and Keeley Brough, both 28, narrowly escaped the attack but the former was injured in the intense gunfire.
Their killers - former school principal Nathaniel Train, his brother Gareth and sister-in-law Stacey - died in a firefight with heavily armed tactical officers after an ambush on the four officers.
The Train brothers' father Ronald Train said he was struggling to comprehend how his sons could be responsible for the murderous attack.
"I just could not understand how something like this could have occurred, with two children who had been raised by my late wife Gwen and myself," the retired pastor told Nine's A Current Affair on Wednesday.
"They went down this track, this dark track, which we have no understanding of."
Police trying to identify the motive for the lethal attack will trace the brothers' online activities, delving into extremist communities online.
"We'll investigate their families, their friends, everything they've done in the last six months to a year," Queensland Police Commissioner Katarina Carroll said.
"We will get to the bottom of this because we need to know what happened and why."
Online posts in the name of Gareth Train featured a myriad of conspiracy material, including claims that high-profile shootings were hoaxes or false-flag operations.
Ronald Train revealed he officiated at the wedding of his younger son Nathaniel and Stacey some years ago, adding he was surprised when he saw reports the older Gareth was now married to the same woman.
The brothers cut all ties with their parents about 23 years ago, he said.
Alan Dare's widow Kerry spoke of her loss, describing her husband as a beautiful man who loved his children and grandchildren.
She was due to celebrate her 26th wedding anniversary on Wednesday but instead she was coming to terms with a life without Alan.
"I haven't thought about it yet ... I've got to be brave," she told A Current Affair through tears.
She said her husband was going to make sure his neighbour was safe after hearing multiple gunshots and seeing black smoke in the area.
Instead, Mr Dare was shot and left for dead.
"If he laid there, he wouldn't have been scared," she said.
"He would have been just looking at the sky and he would have probably been enjoying the view."
© AAP 2022