Three shooters rigged a sophisticated surveillance system to help them "take police out" at a remote Queensland property where they ambushed officers, killing two constables and a neighbour, the police union says.
Forensic examinations are continuing where Constables Matthew Arnold and Rachel McCrow and neighbour Alan Dare were gunned down on a Wieambilla property on the Western Downs, 300km west of Brisbane, on Monday.
Queensland Police Union president Ian Leavers says there's evidence the killers Gareth Train, his wife Stacey, and brother Nathaniel, who were all shot dead, planned the attack and set up a camera system.
