The cops were lured into a trap:
https://www.dailymail.co.uk/news/article-11543639/Wieambilla-shooting-Cop-killer...Ms De Jager said she later received a message from his older brother Gareth who sent her abusive text messages for bringing police into the matter.
Nathaniel remained in contact with some family members but had not been seen since December last year after he quit his job as principal of the Walgett Community College Primary School.
Police issued a public appeal for information following the missing persons report that was made on December 4 - which prompted a phone call suggesting he was north of the border in Wieambilla.
Detectives now suspect the mysterious phone call that lured police to the property
came from the killers, obsessed with prepping for doomsday scenarios.
'They are looking at this possibility that they called NSW police and told them they 'think they know where he is',' a police source told The Australian.
'NSW police acted on that and asked their Queensland counterparts to look into it as part of a routine missing persons' inquiry.
'He was the bait.'
Daily Mail Australia has contacted NSW and Queensland Police for comment on the line of inquiry.
The development comes as new evidence suggests the ambush may have been planned.
Detectives scouring the property in recent days have uncovered the terrifying extent of the 'death trap' set up by the paranoid trio - who were also in a bizarre love triangle.
Investigators told Daily Mail Australia they established a 'kill zone' where they planned to trap any officers who came to the home with an electronic trip wire giving them time to get into their camo gear and load up their weapons.
Police found holes in the siege house walls and so many bullet casings from the 90-minute firefight that they were 'setting off metal detectors like pinball machines'.
An elaborate 'extensive virtual surveillance box' was also set up by the murderous Train trio.