Constables Matthew Arnold and Rachel McCrow were shot in cold blood by Nathaniel and Gareth Train after four officers arrived at their rural property at Wieambilla, west of Brisbane, on December 12, 2022.
At the opening of the five-week inquest in Brisbane on Monday, State Coroner Terry Ryan heard Gareth Train might have had a mental illness that led to a "shared psychotic disorder" or "Folie a trois" with his wife Stacey and brother Nathaniel.
All three Trains were killed by specialist police six hours after the constables were gunned down. They refused to negotiate and opened fire on police helicopters and an armoured vehicle.
Detective Inspector Suzanne Newton told the coroner video evidence as well as fingerprints, ballistics and DNA suggested Nathaniel Train sat in a hunting "hide" made of branches and tracked the officers through his rifle's scope.
Insp Newton said Nathaniel Train could not be seen by the officers as he sat in the hide 185 metres down his driveway that allowed him to survey his front gate, while aiming his high-powered rifle through a pre-prepared gap in the leaves surrounding him.
He opened fire on Const Arnold when he was 70m away.
Detective Inspector Suzanne Newton said the Trains set up a hunting hide to ambush police. (Darren England/AAP PHOTOS)
Mr Ryan was shown harrowing videos of the moments leading up to the ambush and the chaos afterward as some of the officers fired back and did their best to escape.
Counsel assisting Ruth O'Gorman said all six deaths had been recorded in video by either mobile phone, police body-worn or helicopter cameras, but the fatal moments would not be shown.
The four constables climbed over a fence and chatted about their status as junior officers as they entered the property at 4.30pm as part of a routine missing persons inquiry.
"There's a warrant for this fella?" one constable says in the seconds before Ms O'Gorman stopped the video and said Const Arnold was shot in the chest by Nathaniel Train and died.
Ms O'Gorman said Const McCrow showed "great courage and grace" by recording important details about the attackers and a message to her family after she was shot three times in the back and legs while trying to crawl to cover.
Police were lured into an ambush along a dirt road in Wieambilla. (JASON O’BRIEN/AAP PHOTOS)
"She recorded that a shooter was coming towards her. She discharged 15 shots from her Glock (police-issued handgun) and pleaded with the male. There was a brief verbal exchange before she was killed at close range," Ms O'Gorman said.
Mr Ryan heard Gareth Train killed Const McCrow with a single shot to her head from his large-calibre bolt-action rifle.
Constable Randall Kirk took cover behind a tree and tried to call for help on his radio but could not get through, eventually contacting his police station by phone.
Const Kirk told an acting sergeant Const Arnold and Const McCrow were dead and the shooters had rifles and had taken a police Glock.
"You've got to look after yourself, buddy," the sergeant told Const Kirk, who then ran from tree to tree while carrying his gun and being shot at multiple times.
Matthew Arnold and Rachel McCrow were killed in an ambush at a remote property. (HANDOUT/QUEENSLAND POLICE)
Const Kirk reached a police vehicle and sped away from the scene despite suffering bullet wounds to the hip and abdomen.
"There's blood on my face. I don't know if I've been shot," Const Kirk told fellow officers by phone.
Neighbour Alan Dare was shot dead when he came to investigate a fire started by the Trains in an attempt to flush out Constable Keely Brough, who had made it to cover and was concealed by grass less than 20cm in height.
Mr Dare started filming the fire with his mobile phone and said a person was approaching him in a vehicle.
"Oh s***. What the? There was a fight, eh?" Mr Dare said in the seconds before he was fatally shot in the chest by one of the Trains.
The families of two slain officers have called for immediate law changes around firearms registries and police communications.
