Nathaniel Train, 46, and his brother Gareth Train, 47, opened fire on four junior Constables as they walked up the driveway of a remote property at Wieambilla, west of Brisbane, on the afternoon of December 12, 2022.
Matthew Arnold, 26, and Rachel McCrow, 29, died in the ambush while Randall Kirk was able to retreat under fire and Keely Brough hid for more than two hours before rescue.
Nathaniel Train had been reported missing in NSW nearly three weeks before the shootings.
Coroner Terry Ryan previously heard the four officers attended Gareth Train's property at the request of NSW Police for a "door knock" to locate Nathaniel Train and check on his welfare.
Queensland Constable Stephanie Abbott is due to give evidence about the background checks she did in respect of the Trains.
Acting Sergeants Justin Drier and Matthew Minz, officers in charge of the Chinchilla and Tara police stations respectively, will give evidence about their decision to send the four junior officers to the Trains' Wieambilla property.
Mr Ryan previously heard Sgt Drier spoke to Const Kirk on the phone while he was trying to take cover and return fire during the ambush.
Detective Senior Sergeant Duncan Gorrie and Detective Chief Inspector Garry Watts will give their opinions on the decisions made during the missing person investigation.
Nathaniel Train joined with Gareth and his sibling's wife Stacey, 45, to kill neighbour Alan Dare, 58, soon after fatally shooting the two Constables.
All three Trains were shot dead hours later by specialist officers after they refused to surrender and opened fire on a police armoured vehicle.
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