A father claims he was acting in self-defence when he stabbed his adult son to death during an argument sparked by a food delivery driver.
Mehmet Ali Okuman, 54, admits he was the one who inflicted the fatal stab wound to his 33-year-old son Gokhan in January 2025.
But he has pleaded not guilty to murder, with his trial starting in the Victorian Supreme Court on Friday.
Jurors were told Gokhan was at the family's Craigieburn home in Melbourne's north when his father arrived on the evening of January 25.
Gokhan, who had diagnosed mental health issues, had instructed his family not to talk to food delivery drivers because it annoyed him.
But Okuman spoke to the driver that evening as he delivered his son's food before waving at Gokhan through a window.
Those interactions set the 33-year-old off, with Gokhan then texting his sister that his father was a "son of a bitch" and he wanted to be left alone.
Gokhan then began arguing with his father over the delivery driver, with the yelling quickly escalating into a physical altercation.
Okuman's wife and adult daughter tried to intervene as the two men punched and tried to choke each other.
At one point, the women managed to move Gokhan away from his father and into a room on the other side of the house.
But it's alleged Okuman grabbed a kitchen knife and came after his son, striking him with a knife as his wife tried to get in between them.
Gokhan was stabbed to the abdomen, while Okuman's wife was hit in the leg.
Okuman was also injured during the incident, allegedly while his wife tried to pull the knife out of his hand.
She threw the knife into the outdoor patio area and locked the doors so it could not be retrieved.
But it's alleged Okuman then grabbed a glass vase and used it as a weapon, striking Gokhan in the head.
Okuman's daughter called emergency services, telling the call-taker that her father had grabbed a knife and tried to kill her brother.
Police arrived a short time later and spoke to Okuman, who said his "bloody idiot" son had attacked the family three times.
"I stabbed him, the f***ing idiot," he told police.
"That's what happened because he's not stopping."
Gokhan was taken to hospital but died later that evening.
Prosecutor Ruth Champion told the jury Okuman had lost his temper and attacked his son with the intention of killing him.
Defence barrister Moya O'Brien argued her client had been acting in self-defence.
"He used the knife with the belief in his mind that it was necessary to defend himself or others from his son's attack," she told the jury.
"It's the defence case that his actions were a reasonable response to the circumstances."
Ms O'Brien urged jurors to be critical of the evidence from Okuman's wife and daughter.
"Their credibility and reliability will be challenged," she said.
"The truthfulness of what they say will be an issue in this case."
The trial before Justice Amanda Fox continues.
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