An elderly divorcee acted spontaneously when he ran down his ex-wife's new partner before chopping his head with an axe, a judge has been told.
Thanh Tran had not been sitting outside her Sydney residence all afternoon or evening, but must have only been there for a few minutes when he saw his victim outside the house, his barrister said.
Janet Manuell SC was making submissions in the NSW Supreme Court on Friday at the sentence hearing of 79-year-old Tran.
He had denied murdering 59-year-old Pok Min Fah on March 14, 2019, but a jury in October found him guilty of the charge.
Tran, who had no criminal history, didn't deny repeatedly striking him with the axe after hitting him with his car.
But he had argued his judgment was substantially impaired due to a loss of control caused by trauma from his lived experience of Cambodian dictator Pol Pot's regime.
Psychiatrists testified he suffered from post-traumatic stress disorder and depression, but experts differed on whether his impairment was substantial.
Married for more than three decades, the couple had a strained relationship and were in effect separated, with his wife sharing their daughter's bedroom for the last 15 years they had together.
Ms Manuell on Friday said CCTV captured Tran's coming and going to the Mekong Club before the attack, not sitting outside his ex-wife's residence in Cabramatta West.
He must have been there for only a few minutes before he saw Mr Fah outside carrying a ladder, which Tran believed belonged to him.
This may have triggered the spontaneous attack as he obviously thought Mr Fah was responsible for breaking up his family life.
Justice Robert Button said the presence of the axe in the boot of Tran's car was troubling, but Ms Manuell said it was not a new axe.
"Clearly it was an axe that was in his possession for some time," she said.
The presence of binoculars in his car could be explained by his hoping to glimpse his children, being pre-occupied with having contact with them despite their unwillingness.
Prosecutor Katharine Jeffreys accepted there was an element of opportunism involved in the attack and Tran had responded to seeing Mr Fah.
"But I would suggest you would reject complete spontaneity," she told the judge, referring to the presence of the binoculars and the axe.
She said Tran's explanation of having the axe for self-defence only was first suggested by him in cross-examination during the trial.
"I submit he had an intent to kill at least when using the axe and from at least the time he started the car and drove it at the deceased."
The judge referred to the absence of evidence indicating remorse.
No victim impact statements were presented to the court.
Justice Button noted that some people who loved and honoured the memory of a deceased person felt a trial barely mentioned them.
"I think I should assure anyone that the deceased is by no means forgotten and indeed his violent death is the whole reason for the trial and proceedings."
He will sentence Tran on December 9.