A large-scale police search for Vladimir Kondakov, 49, involving the dog unit, PolAir and riot squad began yesterday after the deadly attack about 1pm on Applebee St in St Peters.
The victim has been named as successful Sydney property developer Albert Metledge, 76.
His son, Anthony Metledge, 33, was also stabbed and the knife was left stuck inside him.
He was taken to the Royal Prince Alfred Hospital and underwent surgery for his stab wounds.
Mr Kondakov is described as being of caucasian appearance, about 180 centimetres tall, with a large build and a shaved head.
He speaks with a Russian accent.
He was last seen wearing a blue T-shirt, long blue work pants and brown work boots and may have been carrying a construction helmet and a high-vis shirt.
Police would like to speak to him in relation to the fatal incident.
Members of the public are urged not to approach Mr Kondakov but call triple-0 immediately.
“We believe that he is capable of a violent act which he has done,” Inspector Chad Deegenaars said yesterday afternoon.
He said Mr Kondakov was last seen in the Rockdale area shortly after the stabbing, having reportedly hitched a ride to Brighton-Le-Sands.
“What we do know is that the parties were known to each other. It doesn’t appear to be a random attack,” Insp Deegenaars said.
“We believe the man was working on the site, we’re just trying to establish what the capacity was but he had some involvement with the construction site.”
The wails of a distressed woman, believed to be related to the two Metledge men, echoed throughout the site yesterday.
“I have to say my goodbye,” she turned and said to cameras at the scene.
Other workers on the site described the victim as an “absolute gentleman”, saying the violent attack was “devastating”.
In a public post on Facebook yesterday, Brian Metledge said: “RIP Uncle Albert.”
“The family is in shock and unable to talk or see anyone at the moment. We thank everyone but request privacy at this moment. Please let family and friends know,” he wrote.
In another post, Marlene Oueijane said: “Dear Uncle Albert may you rest in peace with God’s angels. Heartbroken”.
Local detectives and the homicide squad are investigating the circumstances surrounding the incident under Strike Force Tangent.