The former police officer has pleaded not guilty to the murders of Jesse Baird and his new partner Luke Davies after they were shot dead with his work-issued pistol in February 2024.
On a day when jurors heard a triple zero call allegedly made moments before Mr Davies was shot, the NSW Supreme Court was shown new surveillance camera footage showing the senior constable's movements in the hours after the killings.
Three hours after he allegedly murdered the two men on February 19, an undisguised Lamarre-Condon returns to the same sports store in Miranda to buy a second surfboard bag, the footage shows.
Having debated which one to buy with friend Ethan Lynch two days earlier, Lamarre-Condon selects his desired bag immediately off the store rack.
Later footage shows the senior constable outside Mr Baird's house in his hi-vis UberEats disguise, complete with motorcycle helmet, but this time laden with cleaning supplies and a large duffel bag.
A receipt tendered in the trial showed Lamarre-Condon spent nearly $150 in cleaning supplies at Bunnings Alexandria about four hours after the killings.
After being seen on the street an hour later, Lamarre-Condon then walks back towards Mr Baird's house carrying a large blue tarpaulin, the footage played on Friday shows.
The men's bodies were left in surfboard bags in the sharehouse's courtyard overnight.
Lamarre-Condon, who has since left the force, later dumped their bodies south of Sydney and their belongings in a skip bin in Cronulla.
But he argues both men were killed in self-defence in two separate violent struggles and his actions to clean the scene and dispose of the bodies showed his panic.
The perils of CCTV were allegedly on Lamarre-Condon's mind the day before he allegedly murdered Mr Baird and Mr Davies.
The day before the men were shot dead, former officer Ben Higginson says Lamarre-Condon spoke to him about his work on the investigation into the murder of Lilie James in 2023.
Ms James was killed by her ex-boyfriend Paul Thijssen in the bathroom of a gym at St Andrew's Cathedral School in central Sydney.
Lamarre-Condon was "blasé" when discussing the actions of the killer, Mr Higginson told a NSW Supreme Court jury on Friday.
"He thought Paul was stupid for doing it on CCTV," Mr Higginson said.
"He asked, 'If he hadn't done it and then committed suicide, would he have got away with it?'"
The jury also heard a triple zero call allegedly made by Luke Davies seconds before he was shot dead by the officer, allegedly to eliminate a witness to the crime.
All that could be clearly identified in the audio of the call was an operator saying: "I heard a male say, 'Eff off', or dropped out."
Lamarre-Condon's barrister says his client made the call after killing Mr Baird in self-defence but it was cut short by a second, violent struggle where Mr Davies died.
A second former police colleague has also told the jury about a "weird" conversation regarding investigative procedure.
Jurors on Thursday heard from Alexandra Scobie about Lamarre-Condon's alleged questioning about whether records from a phone could still be obtained if the device was switched off.
In the late January 2024 conversation, he also asked her if hire cars could be tracked, she testified.
Sen Const Scobie said she received a rushed phone call from her friend later that night, when he tried to reassure her about his questions.
"I'm not gonna do anything illegal," Lamarre-Condon allegedly told her.
The second of Mr Baird's housemates gave evidence on Friday after her friend told the jury how she was confused to see the surfboard bags leaking a red liquid.
The second housemate, known by the pseudonym Sarah King, said she poked the tarpaulin after seeing it in the courtyard but did not notice anything unusual.
The bags were removed by the next morning and the two men's bodies were taken 200km away, covered with sticks and rocks.
The trial enters its third week on Tuesday.
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