Police say Joshua Colin Duperouzel, 25, may have access to a firearm and should not be approached.
Mr Duperouzel is described as fair-skinned and 186cm tall with a medium build and shaved head.
Anyone who sees him is asked to immediately call triple-zero.
Police are continuing to investigate after 34-year-old Joseph Versace was gunned down at the workshop in Gnangara on Thursday afternoon.
Detectives believe the matter is linked to outlaw motorcycle gangs but are yet to establish the reason behind the shooting.
Police are also seeking information about a black BMW X5 vehicle which was found abandoned in Glen Forrest on Thursday afternoon.
"It is believed the vehicle may have been present at the scene of the shooting in Gnangara," WA Police said in a statement on Monday.
Anyone with information regarding the vehicle's movements in the northern and eastern suburbs on Thursday is asked to contact Crime Stoppers.
Police Commissioner Col Blanch on Friday said detectives were speaking to multiple witnesses but were yet to place a suspect in custody.
A series of raids were carried out over the weekend, with senior Rebels bikie Karl Labrook seen being escorted by police out of a Ridgewood home.
Mr Blanch said the victim was known to police and was believed to have been associated with bikie gangs.
Any retaliatory attacks would be met with a strong police response, he warned.
"This is something that I will not tolerate as commissioner in Western Australia - cold-blooded killings, public acts of violence," he told reporters on Friday.
"If you get out of line, if you start doing things like this, the gang crime squad will come for you."
A recent crackdown on bikie-related crime in WA was spurred partly by the slaying of senior Rebels bikie Nick Martin, who was gunned down from long range by a hired sniper at a Perth drag racing event in December 2020.
The gunman, a former soldier who cannot be named for legal reasons, pleaded guilty to Martin's murder last year and was jailed for at least 18 years.
Former Rebels bikie David Pye is accused of organising and paying for Martin's killing. He has been charged with murder and other offences but is yet to enter pleas.
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