Hundreds of "shots fired" incidents were recorded by police around a rural property where six people were later killed and some serious reports were not fully investigated, a coroner has heard.
Constables Matthew Arnold, 26, and Rachel McCrow, 29, were killed in a sniper ambush at Wieambilla, west of Brisbane on December 12, 2022 while serving an arrest warrant.
Detective Inspector Suzanne Newton, lead investigator on the deaths, testified on Thursday she compiled a list of 277 "shots fired" reports in a large area around Wieambilla in the four years before the fatal shootings.
State Coroner Terry Ryan heard evidence Nathaniel Train, 46, and his brother Gareth Train, 47, shot the constables then killed their neighbour Alan Dare, 58.
The two brothers along with Gareth Train's wife Stacey, 45, were killed later that night after shooting at specialist police.
Det Newton said a Wieambilla resident had reported to police a person had trespassed on their property and fired a shot at their dog in the month before the fatal incident.
Counsel assisting Ruth O'Gorman asked if the report and four others within a 30-minute drive of the Trains' property were followed up by police and not linked to the family.
"Correct," Det Newton said.
Detective Acting Inspector Aaron Baxter testified officers were "generally adequate" when responding to reports of a bullet striking the ground near a man and his dog 500 metres from the Trains' property.
"A crime report should have been generated as opposed to a street check (which) is just some information that doesn't require any further investigation," he said.
Det Baxter said the Trains were never linked to previous shooting incidents and police had updated procedures for handling shots fired in rural areas.
Nathaniel Train illegally crossed into Queensland from NSW with a cache of firearms during a COVID-19 border lockdown nearly 12 months before taking part in the Wieambilla shootings.
Mr Ryan heard an associate of Nathaniel Train give evidence about the period when the 46-year-old left for a camping trip that turned into a near-disappearance.
The associate cannot be identified because of a court order handed down before the inquest began.
The associate said they had accessed Nathaniel Train's email account after his older brother Gareth had told them not to attempt to contact his sibling.
A barrister asked the associate about "incredibly disturbing" emails they saw in that account on December 10, 2022 written by Gareth Train threatening "graphic" consequences for continuing to report Nathaniel Train as missing.
"He had already expressed anger. I just thought he was a keyboard warrior," the associate said.
The associate had filed a missing persons report on December 5, 2022, which was treated as high risk because of Nathaniel Train having stopped taking heart medication.
The associate forwarded the emails to the NSW police officer investigating the missing persons report on the weekend before the shootings, but they received an out-of-office automated reply.
In the hours after he fatally shoot police, Gareth Train sent his brother's associate a text message that stated: "You sent people to kill us. Run".
The associate said Nathaniel Train had been under significant stress and suffered a heart attack in August 2021 while working long days as a principal at a highly disadvantaged school in regional NSW.
Mr Ryan heard the associate thought Nathaniel Train was leaving for a short trip to Queensland to see his children.
"He was very emotional. Very teary ... it seemed things had become insurmountable for him. He needed time out," they said.
A forensic psychiatrist has previously testified the Trains likely suffered from a "shared psychotic disorder" with Gareth Train as the primary sufferer who acted on extreme religious beliefs and conspiracy theories.
Nathaniel Train travelled to Wieambilla in January 2021 and heard Gareth Train detail his "grand opus" that numerous secret societies, COVID and other disasters were all connected to the world ending soon via a final battle between Jesus Christ and Satan.
"(Nathaniel Train) told me they just talked about God," the associate said.
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