David James Pye, 43, stood trial in 2025 charged with murder over the December 2020 slaying of senior Rebels bikie Nick Martin at Perth Motorplex.
Pye is accused of hiring an ex-army reservist, who cannot be named for legal reasons, to carry out the public assassination.
A judge will deliver his verdict on Friday.
It's alleged Pye paid the gunman $100,000 to carry out the hit on his one-time ally, after the relationship between the two bikies soured when Pye defected from the Rebels to the Comancheros.
The shooter, who is serving a 20-year prison sentence after pleading guilty to murder, used a .308-calibre rifle to target Martin from a distance of more than 300 metres while he sat with his loved ones in a spectator area at the racetrack.
The bullet travelled through Martin's body and exited from his lower back before striking another man in his arm, seriously injuring him.
The court was told the assassin later received a message from Pye that consisted of two coffin emojis and a hand clap emoji.
"One dead, one serious," Pye was alleged to have said.
Pye faced a judge-alone trial in the West Australian Supreme Court after pleading not guilty to six charges, including murder.
The sniper gave evidence at the trial that he visited Pye's home after the shooting, where his cash payment for killing Martin was waiting for him in a Woolworths bag, but only found half of the $100,000 cash.
Pye allegedly replied with words to the effect of "the other person didn't put in - it is what it is".
During the trial, the assassin said Pye was the "dodgiest person I knew" and alleged Pye had told him he wanted to "blow holes" in Martin.
The trained marksman confirmed he described his hit on the bikie boss as a "community service", saying it was "probably my state of mind, yes".
Pye's barrister, David Hallowes SC, argued the shooter was a liar and the bikie never asked him to kill Martin.
Prosecutors also alleged Pye offered to pay the same shooter to murder his ex-girlfriend and another bikie, but their killings never eventuated.
Justice Joseph McGrath will deliver his verdict on Friday.