Constables Matthew Arnold, 26, and Rachel McCrow, 29, were gunned down as they walked up a driveway of a rural property west of Brisbane on December 12, 2022.
They were among six people killed in the Wieambilla shootings, also including local good Samaritan Alan Dare.
After five weeks of confronting evidence in 2024, State Coroner Terry Ryan will release his findings in Brisbane on Friday into what Queensland Police described as a "religiously motivated" terrorist attack.
Const Arnold and Const McCrow were supposed to be attending a routine job at Gareth and Stacey Train's home - but it would be their last.
The officers thought it would be a quick visit to try and find Gareth Train's brother Nathaniel, missing from NSW.
The heavily armed brothers opened fire, killing the officers in cold blood before neighbour Mr Dare was shot while investigating the noise.
The Trains were later killed in a hail of gunfire when a Special Emergency Response Team stormed the property.
While the heartbroken families face their third Christmas without their loved ones, they hope the coroner's findings will deliver some answers.
Judy McCrow, mother of slain officer Rachel, spoke at the inquest on behalf of grief-stricken police families, calling for immediate law changes around firearms and police communications.
"There is no escaping our devastating loss, the all-consuming grief and the tears. Our collective heart remains broken beyond repair," she said.
"We pose this question to authorities: could a national firearms and ammunition register, drones and satellite-based communication strategies reduce the current risk?"
The tragedy unfolded when NSW Police officers asked Queensland counterparts to attend the remote bushland block to locate Nathaniel Train.
The former regional NSW primary school principal fled after a heart attack and retreated to the home of his ex-wife, Stacey Train, 45, who married his 47-year-old brother Gareth.
The trio lived in isolation, descending into dangerous delusions that culminated in the bloody ambush.
Authorities later declared it was the first time Christian extremist ideology was linked to a terror attack in Australia.
Counsel assisting Ruth O'Gorman told the inquest the trio had a "shared psychotic disorder", with Gareth Train the primary sufferer.
"The Trains were motivated by religious conviction that the end times were imminent … their religious extremism was a key driver for their actions," she said.
The Trains' Christian premillennialist belief in an impending apocalypse and final battle with Satan was predated by their shared delusion they were being persecuted by a range of authorities, particularly police.
After considering the evidence for 14 months, the coroner will deliver findings on nine major issues ranging from the deaths' circumstances to police communications.
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