Accused former police officer Beau Lamarre-Condon said "pew pew" and made a shooting gesture to demonstrate how he killed two men, a jury has heard.
Lamarre-Condon, 31, has pleaded not guilty to the February 2024 murders of his ex Jesse Baird and Mr Baird's new boyfriend Luke Davies, whose bodies were found at a rural property inside surfboard bags.
The former senior constable says he killed the men in self-defence inside Mr Baird's Sydney terrace and then "panicked considerably" disposing of their bodies.
A friend of the accused, who cannot be identified for legal reasons, gave evidence in the NSW Supreme Court on Friday about interactions with the accused man on February 19, the day the two men died.
After being told to come out from his workplace and meet Lamarre-Condon in a strange car, the friend asked the accused what was going on.
"I've done something ... I've killed people," Lamarre-Condon allegedly said.
When asked how he killed them, the sworn police officer allegedly made a firearm gesture with his hand and said: "Pew pew".
"I shot the first one through the head and the second one through the door," the friend recalled Lamarre-Condon saying.
"He heard ... someone trying to call police and couldn't leave any witnesses ... the second person wasn't meant to be shot," the friend told the court.
The Crown alleges Mr Davies was shot through Mr Baird's bedroom door.
But Lamarre-Condon's barrister has suggested Mr Davies was killed in a violent struggle for the officer's police pistol.
The friend also gave evidence about a trip to a Decathlon sports store in Sydney's south two days before the killings, footage of which was earlier shown to the jury.
The friend said Lamarre-Condon told him he needed to collect surfboards from Mr Baird's house because he had left them there during their relationship.
But the man said he was confused by the conversation given his friend had never once spoken about an interest in surfing.
"We went to Bali and he didn't surf," the friend said.
"When I went surfing, he just went and did his own thing.
"I didn't know he surfed before we went inside."
In CCTV shown to the 15-member jury earlier in the trial, Lamarre-Condon can be seen holding up a bag next to his friend before selecting a bigger one.
"He then asked me: 'You're about the same size as my surfboard, can you stand up to it so I can measure it?'" the friend recalled.
"I might just get the bigger one," Lamarre-Condon said after the measurement, the friend testified.
Lamarre-Condon only bought one bag while shopping with his friend, but footage showed him buying a second bag from the same store hours after he allegedly murdered Mr Baird and Mr Davies.
The trial continues.
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