The 31-year-old has pleaded not guilty to the murders of his ex Jesse Baird and their new partner Luke Davies after they were shot dead with his police pistol in February 2024.
Through his lawyer, the former officer says 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.
But a former police colleague of Lamarre-Condon told the NSW Supreme Court jury about a conversation where the accused officer asked questions about investigative procedure.
Lamarre-Condon asked Alexandra Scobie in late January 2024 whether records from a phone could still be obtained if the device was switched off, she told the court.
"Why are you now asking me that ... he worked at (police charity) PCYC," Sen Const Scobie recalled thinking when asked the question.
He also asked her if hire cars could be tracked, she said.
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," he allegedly told her.
Sen Const Scobie recounted a conversation where Lamarre-Condon was "really angry" about Mr Baird's new relationship with Mr Davies.
"He wasn't happy at all," Sen Const Scobie said.
"We were really reiterating 'you need to move on and let it go.'"
On February 19, the senior constable disguised himself as an UberEats driver and entered his ex's house armed with his police pistol.
While the exact circumstances of how Mr Baird and Mr Davies died are yet to be determined, it is not disputed that both suffered fatal gunshot wounds and their bodies were left in surfboard bags in the house's courtyard overnight.
The second of Mr Baird's housemates is expected to give evidence on Friday after her friend told the jury how she was confused to see the bags leaking a red liquid.
"I thought it was rusted water from the outdoor furniture," the housemate known by the pseudonym Belinda Smith said.
The bags were removed by the next morning and the two men's bodies were taken 200km away, covered with sticks and rocks.
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