The Daily Telegraph can reveal that Zeljko "Steven" Mitrovic, 45, a long-time member of Hells Angels, was found with several gunshot wounds to his body after a gunman opened fire at his family-run business on Hassall St, Wetherill Park about 3.50pm.
He was pronounced dead at the scene while another man, aged 31, was taken to Liverpool Hospital with a bullet in his right arm.
He remained in a stable condition last night.
Scores of police and paramedics descended on the premises as detectives set up strike force Lambourn, using officers from the Homicide Squad and Gangs Squad, to figure out a motive for the cold-blooded attack.
Officers yesterday confirmed that a "person of interest" had been identified in relation to the shooting and was last night being sought for questioning.
A number of visibly-upset family members, including children, also came to the scene, described by police as "tragic", in the hours after the attack, consoling each other.
Senior police sources yesterday confirmed the two victims of the attack were not related but both worked at Mitrovic's logistics company, Dynamic Transport Australasia. Acting Superintendent Stephen Thomas said positive lines of inquiry had been identified.
"We are looking for a person of interest in relation to this particular matter," Supt Thomas said.
"The family has been present on the scene, they are very distraught by the situation.
"We are seeking assistance from the public in relation to any information that they may have in relation to this incident."
The Serbian-born businessman and married father has a lengthy criminal history and was well-known to Gangs Squad police.
Mitrovic came to prominence with police in 1998 when he was charged over the double-murder of Orhan Yildirim, 41, and Mehmet Unsal, 33.
Police arrested him alongside seven other men, including senior Bandidos outlaw motorcycle gang members Russell Merrick Oldham - now deceased - and jailed outlaw bikie bodyguard Raymond Curry.
He was also closely linked to the now former national president of the Hells Angels, Derek Wainohu, and is believed to have been a member of Wainohu's Guildford chapter. Both Mitrovic and Wainohu appeared in court together in 2007 after being arrested over the assault of two 23-year-old men outside a business in Guildford.
Mitrovic was charged with assault occasioning actual bodily harm, affray and assault - at the time he was on parole for a previous offence.
Nearby workers had to clear the area after the attack, and many took to social media to report the commotion.
One man said he knew nothing of the matter until a flurry of police cars flew by.
"I was working literally across the road and I didn't hear any gunshots ... but I seen around 6-8 cop cars and 5 ambulance," the man said.
Additional reporting: Carleen Frost