Constables Matthew Arnold, 26, and Rachel McCrow, 29, along with 58-year-old resident Alan Dare, were killed in a hail of bullets at a rural property at Wieambulla in the western Darling Downs region on Monday.
Constables Randall Kirk and Keeley Brough, both 28, escaped, but the former was injured in the intense gunfire.
Const. Kirk, who is expecting his second child with his wife Bree next month, was due to be released from the hospital on Wednesday after recovering from surgery to remove shrapnel.
The couple said they were overwhelmed by the messages of support from the public and "everyone from the prime minister down".
"It means a lot to know the community cares for us all."
"The constables were so young and brave, and Alan Dare, an innocent bystander," Palaszczuk tweeted.
"For them, it's very difficult ... they were there when their partners were killed," Carroll told ABC TV.
Their killers—former school principal Nathaniel Train, his brother Gareth and sister-in-law Stacey—died in a firefight with heavily armed tactical officers after the attack on the four officers.
Hundreds of rounds were exchanged before the trio were shot and killed.
Investigators are probing the motive for Monday's attack, including whether the officers were lured to the property after following up on a missing person report for Nathaniel Train.
They will also examine how the brothers were able to stockpile a cache of lethal weapons, including high-powered firearms, knives and axes.
The weapons had been legally obtained but were registered in the neighbouring state of New South Wales, a source said, prompting calls for changes to national gun registration laws.
Investigators will also explore the killers' motivations, and possible extremist links after a series of posts under the name of Gareth Train were uncovered on conspiracy theory forums.
The posts include references to anti-vaccine sentiments and claims high-profile shootings were hoaxes or false flag operations.
The brothers' father, Ronald said Gareth had always been a volatile and overpowering person who was obsessed with weapons and guns.
The Train brothers cut ties with their parents 23 years ago, but the retired pastor said he was still shocked the pair went down this violent path.
"They've been demonised by what's occurred, and I can completely understand that," Train told A Current Affair on Wednesday night.
"(They were) two boys who completely lost their way in life."