The daughter of people who gunned down two police officers and a neighbour at a rural property says NSW Police didn't warn the Queensland force of their mistrust of police.
Stacey, Gareth and Nathaniel Train killed Constables Rachel McCrow and Matthew Arnold and neighbour Alan Dare at a Wieambilla residence, three hours west of Brisbane, on December 12.
The offenders died in a gunfight later that night with specialist police.
Madelyn Train, the biological daughter of Nathaniel and Stacey, told Nine News on Monday she missed a call from a police officer in Walgett in northern NSW on the day of the killings.
Ms Train said no officers should have been sent to the property until police had relevant background information.
She said Nathaniel Train's wife Vanessa had told NSW authorities of the group's mistrust of police.
"They were contacting us to ask if Nathaniel was missing and to get contextual information but they never should have sent anyone there until they got all the contextual information," she said.
"(Vanessa) had told the police officers that there was a mistrust of police, like Gary (Gareth) had a mistrust of police, and then the NSW Police Force apparently did not disclose that to the Queensland Police Force."
Queensland Police said at the time of the shooting they knew little about the Trains and there was nothing that would have raised particular concerns for officers on the day.
Madelyn Train earlier told Nine News her mother didn't like guns.
Ms Train was raised by her "uncle Gary" (Gareth), who she called dad after Stacey married him following her divorce from Nathaniel.
"They were the gentlest people I know," Ms Train told Nine News on Sunday.
Ms Train said there was nothing to indicate they would commit the mass shooting but her "dad", Gary, did hold extreme views.
Ms Train said the three were "influenced by fear" in committing the shootings.
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