The shooting in rural Queensland last year which killed three people has been deemed a terrorist attack motivated by religious extremism.
In December last year Nathaniel, Gareth and Stacey Train gunned down two police officers and a neighbour on their property in rural Australia.
The trio killed Constable Rachel McCrow, 29, Constable Matthew Arnold, 26, and neighbour Alan Dare.
Deputy Commissioner Tracy Linford said on Thursday (local time) the shooting had been deemed as a terrorist attack and the Trains "acted as an autonomous cell and executed a planned attack directed at police".
"We don't believe this attack was random or spontaneous," Deputy Police Commissioner Linford said. "We do believe it was an attack directed at police.
"There was significant evidence of advanced preparation and planning."
During their investigation officers found a cache of weapons, camouflaged hiding places, barriers, radios and mirrors on trees at the property.
Linford said the Trains subscribed to "what we would call a broad Christian fundamentalist belief system, known as premillennialism".
"Whilst the behaviour was similar in some respect to sovereign citizens, we don't believe this was connected to a sovereign citizen ideology, we believe it's connected to the Christian extremist ideology," she said.
She told media the Trains believed Christ would return to earth and provide peace and prosperity. But Linford said they believed this would be preceded by an era of tribulation, widespread destruction and suffering.
"They started preparing for the end of days," she said.
How the shooting unfolded
Four officers were attending a property in Wieambilla, in the Western Downs region west of Brisbane, to make enquiries regarding a missing person.
The missing person was Nathaniel Train who was reported missing a few days before the attack.
Train's brother Gareth was there too along with Stacey.
All three were shot and killed by special operations police in a gunfight after a massive manhunt.
