Millionaire property developer Ron Medich murdered his former business partner because he felt humiliated and angry that Michael McGurk was "making a fool of him," a Supreme Court jury has heard.
Mr Medich, 68, has pleaded not guilty to the murder of McGurk, who was shot in the back of his head outside his Cremorne home on September 3, 2009.
He has also pleaded not guilty to the subsequent intimidation of McGurk's widow Kimberley on August 8, 2010.
In her opening address, Crown prosecutor Gina O'Rourke, SC, told a jury that Mr Medich and McGurk had once been close business partners but had fallen out over a number of soured business and property deals.
By early 2009, Mr Medich had developed a "strong desire" to have McGurk permanently removed from his life as the two were embroiled in a number of messy legal action suits, with each accusing the other of owing millions of dollars.
McGurk, a 45-year-old wheeler-dealer, was shot only days after a firebombing charge against him was dropped.
His nine-year-old son, who was in the front seat of his father's car when they pulled into the family's driveway, raced into the house to get help – but it was too late.
The Supreme Court heard that as McGurk's star was falling with Mr Medich, the property developer turned to a long-term friend and associate, Fortunato "Lucky" Gattellari.
The evidence would show that Mr Medich and Gattellari were "joined at the hip" and that Gattellari's major role in Mr Medich's life was "to keep him company", Ms O'Rourke told the jury.
In early 2009 Mr Medich allegedly told Gattellari: "I need to put an end to this". He said he wanted McGurk dead and that Gattellari was to organise the hit, the Crown prosecutor alleged.
The court heard that Gattellari, who pleaded guilty over his role in the murder of McGurk and the subsequent intimidation of McGurk's widow, was given $500,000 in cash from Mr Medich to achieve these two outcomes.
When Mrs McGurk did not settle all the legal actions after her husband's death, Mr Medich allegedly said of her: "The f---ing bitch has got to get the message. I am sick of it."
Central to the actual murder of McGurk and the intimidation of Mrs McGurk was Haissam Safetli, who has also pleaded guilty.
When Mrs McGurk refused to pay the millions of dollars Mr Medich was demanding, Gattellari once again turned to Safetli, the court heard.
However, Safetli subcontracted the intimidation to an associate not realising this person was a police informant.
In August 2010 the police informant, wearing a coloured wig, told Mrs McGurk not to be a "conman" like her husband and to pay her husband's debts.
Days later Mr Medich was rattled when property developer Bob Ell and his friend Richie Vereker invited him to lunch where they told him to stop harassing Mrs McGurk, saying: "You're the only one she owes money to."
Ms O'Rourke told the jury that she expected the credibility of the Crown's chief witness, Gattellari, would be "extensively challenged" by the defence, but that he had only met McGurk four times and had no financial dealings with him.
Ms O'Rourke said that following Gattellari's arrest in October 2010, an associate came to ask Mr Medich for assistance with his legal costs. "Be careful what you say," Mr Medich allegedly warned. "The walls have ears."
The trial is expected to run for three months. One of the first witnesses to be called is Mrs McGurk.
Earlier, Justice Geoff Bellew warned the jury that it was a potential two-year jail term if any juror was caught conducting his or her own research outside the court. This included using Google or searching social media sites such as Twitter, Facebook and Instagram.
He also said the case had attracted a great deal of publicity and was bound to attract further media coverage. "Your responsibility is to ignore it," said Justice Bellew.
"Blame it on me, I don't mind," said the judge, as he forbade jurors to discuss any aspect of the case with family or friends.