An elderly man who brutally murdered his co-worker with a stake in a Sydney scrap metal factory should spend no longer than 15 years behind bars, a Sydney judge has ruled.
Do Hyun Chong, 70, murdered his supervisor and housemate Jong Hwa Park, 32, during a "savage, brutal and sustained beating" inside the King's Smelter scrap metal factory at Wetherill Park, in Sydney's west, on May 17, 2009.
During the final blows with a metal stake, Chong stood on Park's lower back and "mercilessly beat him to death".
Two months after Park's death, and before Chong had been charged with his murder, Chong's car collided with a truck, severely injuring him.
Chong suffered "catastrophic brain damage" and has permanent intellectual disabilities which have left him with no recollection of the crime.
He was ruled unfit to go to trial.
In a special hearing in September, a jury found that Chong had committed the offence of murder.
In the NSW Supreme Court on Friday, Justice Robert Allan Hulme told the court that taking into account Chong's age and mental state he should serve a limiting sentence of 15 years.
"I am satisfied that Park's death was the result of a savage, brutal and sustained beating by Chong using a metal stake," Justice Hulme told the court.
"There is no evidence to suggest he had any mental health issues or impairment at the time of the offence."
The limiting sentence is the period of incarceration Justice Hulme would have imposed on Chong if he had been convicted of murder in a normal trial.
The 15-year sentence will now be reviewed by the Mental Health Tribunal, which will consider Chong's mental state, prospects for improvement and progress before ruling on Justice Hulme's recommendation.
The matter will then return to the Supreme Court for sentencing.
On Friday, the court heard that Park, who had been sent from South Korea two months prior to his death to supervise Chong at the factory, was having trouble living and working with the elderly man.
"At one point Park said if anything happened to him it would be Chong's doing," Justice Hulme said.
Park had been sent to Sydney after the owners of the scrap metal company discovered Chong had embezzled more than US$200,000.
The court heard Chong was not happy about the arrangement and often swore at Park and threatened him.
Justice Hulme told the court a medical report showed Chong had no memory of killing Park and did not understand why he was being held in the aged care and rehabilitation facility at Long Bay Prison.
"Time in custody will be more onerous for Chong because of his impairment," he told the court.