Detectives are investigating criminal gang links to the the weekend shooting at a Melbourne nightclub that's likely to claim a second life.
One man died in the drive-by shooting at Prahran venue Love Machine on Sunday morning, and another man is not expected to survive his injuries.
Links to outlaw motorcycle gangs and Middle Eastern organised crime groups are being examined as part of the "thorough" investigation into the shooting.
"We think this is quite a specific, targeted attack, but we do not understand the motive, nor the people who are involved in it at this time," Victoria Police Crime Command Assistant Commissioner Tess Walsh told reporters on Monday.
"Clearly there are tensions escalating."
A 28-year-old man, who has been in a critical condition in hospital since the shooting, is not expected to survive gunshot wounds suffered while lining up to enter the club as a patron.
Security guard Aaron Khalid Osmani, 37, was also rushed to hospital after the shooting and died later the same day. Three other men were injured by the shots fired from a stolen black Porsche SUV about 3.20am.
One of them, 26-year-old Ali Shohani, told Nine News he saw colleague Mr Osmani shot in the face.
"It was like a war zone," the Love Machine worker said of the scene.
Mr Shohani later drove himself to hospital and had a bullet removed from beneath his skin.
A police hunt is underway for the killer. The Porsche, which was stolen from Dandenong in March, was found burnt-out in Wollert after the shooting.
Ms Walsh said there was no evidence to link the nightclub shooting to other recent fatal gun attacks, including one at a boxing match.
"We are extremely confident we will solve this crime and this horrendous murder," she said.
Detectives are asking for public information to help solve the crime.
"Innocent people have been impacted in the most serious way," Ms Walsh said.
Victoria's political opposition said Sunday's shooting is further proof of an "alarming increase of gun violence".
"This is the sixth shooting fatality in six weeks which is six too many. There are also serious concerns that several of these shootings are gang related," opposition police spokesman David Southwick said.
He called on the Labor government to "get serious" about tackling organised crime.
NIGHTCLUB SHOOTING - THE DEAD AND INJURED
* Security guard Aaron Khalid Osmani, 37, from Narre Warren South. Died in hospital on Sunday.
* 28-year-old male patron from Maidstone. Critical condition. Not expected to survive his injuries.
* 50-year-old man from Gisborne. Non-life threatening injuries.
* 29-year-old Dallas man. Non-life threatening injuries.
* Meadow Heights man Ali Shohani, 26, attended hospital with injuries on Sunday.
* 20-year-old woman fell and hit her head as people fled the shooting.
Australian Associated Press