After two men were arrested on Monday over the early morning attack in Sydney's west, police arrested another man on Tuesday evening after stopping and searching a car.
Police allege a 38-year-old man was set upon by a group of heavy-set, black-clad men in a targeted shooting inside a unit in Lidcombe, near Sydney Olympic Park, about 4am on Monday.
He was rushed to hospital with serious gunshot wounds but died shortly after.
A second man found at the scene was taken to hospital with non-life threatening injuries.
Police earlier revealed they believed the shooting was carried out by offenders with links to organised crime.
"This is a targeted attack. This is not a random attack," Superintendent Robert Toynton told reporters.
Officers arrested a 21-year-old man on Monday afternoon after a car crashed into a parked vehicle.
Detectives then raided a home on Spurway Street in Ermington, near Lidcombe, about 8pm and arrested a 22-year-old man.
Both men were charged with murder and refused bail.
On Tuesday evening, police stopped a black Volkswagen Golf in the car park of Norton Plaza in Leichhardt, where a 19-year-old male passenger was arrested.
Detectives searched the car and found a plastic bag containing cable ties, gloves, and clothing.
He was taken to Surry Hills Police Station and charged with murder, wounding a person with intent to cause grievous bodily harm and dealing with property suspected to be from the proceeds of crime that's valued at less than $100,000.
He was refused bail and is due to appear at Burwood Local Court on Wednesday.
Detectives say investigations into the shooting are ongoing.