AUSTRALIAN police say they are investigating the extremist views of three people who shot and killed two police officers and a neighbour at an isolated rural property in Wieambilla, Queensland.

The shooting took place after four officers were called to the remote property on Monday.

The shooters were killed hours later by police in a gunfight.

The killers have been identified as former school principal Nathaniel Train, his brother Gareth, and sister-in-law Stacey.

They ambushed and shot dead constables Matthew Arnold and Rachel McCrow, before killing neighbour Alan Dare when he came to help. 

Queensland Police Commissioner Katarina Carroll said on Tuesday that investigators would look at the possible extremist links of the killers after a series of posts under the name of Gareth Train were found on conspiracy theory forums.

The posts include references to anti-vaccine sentiments and claims that other high-profile shootings were hoaxes or false-flag operations.

One post refers to “black-op police” and urges people to prepare themselves.

“It’s very difficult at the moment for us to reason with what has happened, there are no obvious reasons,” Ms Carroll said. 

But she said that she had no doubt that over the coming days and weeks, police would come back with some insight into the tragic events that unfolded.

“Some of the stuff that’s online from these people, we will investigate what they have been doing not only in recent weeks but in recent years, who they’ve been interacting with,” she said.

One of the officers that escaped, Constable Randall Kirk, is recovering at a hospital from shrapnel wounds. 

He said that he and his wife wanted to thank everybody for their messages of support.

“I’m feeling fine, just a little sore. My main thoughts are with the other police families at this awful time,” Mr Kirk said in a statement released by the police union.