Police have revealed the “sickening lengths” three shooters went to setting up a surveillance system on their fortified Queensland property to “take out police”.

Forensic examinations are continuing where Constables Matthew Arnold and Rachel McCrow and neighbour Alan Dare were gunned down at Wieambilla on the Western Downs on Monday.

Queensland Police Union president Ian Leavers said disturbing evidence uncovered on the remote property pointed to the trio planning their deranged attack.

“It was a sophisticated surveillance system and that is very, very concerning to us, knowing that this ruthless, murderous trio went to this extent with a view to I firmly believe, to take police out,” he told ABC Radio on Thursday.

“As other investigations are continuing, I’d like to be able to say more, but I can’t because I’m very cognisant of the investigation, I don’t want to hamper it, but we are very, very concerned, and it’s sickening to know the lengths that this murderous trio went to.”

It comes as fresh audio from the firefight between front-line and specialist police and the killers reveals more details of the dramatic siege.

PolAir officers in choppers were guiding the Special Emergency Response Team (SERT) officers on the ground as they battled the Trains.

Siege unfolds

A blow-by-blow transcript shows the brothers were actively firing at police for an extended period, using a ute for cover, while Stacey was unseen for some some.

“Both POIs (person of interest) now weapons are facing white side and as you can see there, they’ve got the spotlight on top of the utility and discharging weapons white side,” the audio says.

“Single male discharging his weapon, so main POI discharging the weapon has moved to the rear of the utility. The second male is sitting on the stairs, on the red side stairs.

“From what I’m looking at the main POI is obtaining rounds and loading the weapon from the rear of the utility.

“POI back open driver’s door, weapons resting on the door. Weapons facing white side. Weapons discharging white side.

“So, the main POI is now at the rear of the utility, and it would appear he has a number of cartridges on the rear tray and that is where he is reloading his weapon.

“Ahhh unable to ascertain that. We’re not getting a response from our (inaudible). There have been no indicators. The second male POI is sitting on the stairs on the red side access stairs. The female is unsighted, assumed to be (inaudible).”

Shots were going off “every five seconds” according to the audio.

The police then spot a “pair of legs” on the balcony, which they identify as being Ms Train.

Not long after, police call “female down, female down” as it appeared Ms Train was hit and POI1 was also showing “no movement” as POI2 continued to discharge rounds.

“Two’s moving, down on the ground beside the vehicle. Standing up.

“No.2 is down. Still has movement. Dropping to the ground.

“PolAir to SERT, he’s down on the ground. (Inaudible) facing the vehicle, no movement.”

It goes on: “PolAir to SERT, still have movement of number 2. Down on the ground, laying on his left-hand side, behind the couch, facing the vehicle.

“PolAir SERT, no movement from number 2. No movement from No.2.”

Survivors return home

Mr Leavers said the dual police and union investigations could take another week to work out what happened to Constables Arnold, 26, and McCrow, 29, and Mr Dare, 58, and why.

Constable Keely Brough, 28, who escaped the ambush by hiding in long grass, which the shooters then ignited, was taking time off with her family, he said.

Her colleague, Constable Randall Kirk, who also got away, is recovering at home with his pregnant wife and daughter after having surgery to remove shrapnel from his leg.

Mr Leavers said Constable Kirk may need further operations, but both officers are doing as well as they can.

“We are so very fortunate that Randall and Keely are still with us as well, it was close,” he added.

Constable Kirk with wife Breanna. He is now out of hospital and recovering at home. Photo: Facebook/QPU

Parliament honours officers

The Prime Minister and Opposition Leader paid tribute to the fallen officers in Federal Parliament on Thursday.

Prime Minister Anthony Albanese thanked all officers involved for their courage in the line of fire.

“It should have been an ordinary summer’s day on the Western Downs, a day of warmth under that big blue sky,” he said.

“Instead that quiet was shattered by the gunfire of an atrocity, a vicious and deadly ambush that has stolen lives, broken hearts, devastated a community and shocked our nation.”

An emotional Peter Dutton broke down in tears and Nationals counterpart David Littleproud also choked his way through a speech.

Mr Dutton, a former Queensland police officer, said “three wonderful Australians” had paid the ultimate price while serving their community.

“Three people who embodied compassion, commitment and courage during their lives and in their final moments,” he told parliament.

Mr Littleproud, the MP representing the area, said the fallen officers were “the greatest locals we’ve ever had”.

“They had pure intent to serve their community, and they were met with malicious intent, with a vile outcome that shattered the innocence of two small country towns,” he told parliament.

“”The bravery … being able to escape a situation they weren’t prepared for, they had no intelligence it was coming, is something mere mortals would find hard to comprehend.”

Earlier, Mr Dutton said Australians should be concerned about the rise of anti-authoritarian “lunacy” shown by the killer Train family.

Mr Dutton said the anti-government rhetoric being shared should concern any “right-thinking Australian”.

“We’ve seen in recent years the spread of disinformation on the internet and the way in which that infects people’s minds and changes their whole persona, their whole perspective and causes them to commit … extreme acts,” he told reporters.

“You worry about the information your children are accessing online … they can be encouraged to spread all sorts of conspiracy theories and subscribe to those and spread that hatred and we should be very concerned about that.”

-with AAP