An envious martial arts instructor who once lied about competing in the Olympics will die behind bars after viciously murdering two parents and their seven-year-old son.
Kwang Kyung Yoo strangled a 41-year-old mum before teaching a class and then strangling the young boy at his studio at North Parramatta in western Sydney in February 2024.
He took the woman's Apple watch and drove her BMW to the family's home in Baulkham Hills where he fatally stabbed the 39-year-old father.
The taekwondo teacher formerly known as Master Lion sat with his head bowed in the NSW Supreme Court on Tuesday as he was hit with a life sentence for his crimes.
The 51-year-old South Korean did not look at the victims' family and other supporters as they sobbed in the court's public gallery after the extreme sentence was handed down.
Their friends told reporters outside court that they were happy with the result.
Justice Ian Harrison found the three murders were objectively very serious, motivated by a financially struggling Yoo becoming jealous of the family's success.
“These killings were horrific and violent acts, senselessly cruel and cynical, perpetrated without a trace of human compassion," the judge said.
A life sentence sent a message to the community that murdering people for effectively no reason at all would not be tolerated, he told the court.
He set no parole date, meaning Yoo will die in prison.
Murdering the vulnerable boy was an egregious breach of trust after he and his mother had been lulled into a false sense of security unaware of the terrible fate that awaited them, Justice Harrison said.
While the crimes were planned - with Yoo surveilling the family's home beforehand - he made no attempt to conceal his crimes from the CCTV cameras within the taekwondo studio or try to conceal the bodies.
At a sentence hearing in November, the judge heard Yoo had lied about meeting Gina Rinehart, qualifying for the 2000 Olympics, owning a Lamborghini and living in Sydney's wealthy eastern suburbs.
To impress his own wife, he would send emails to himself, pretending to be important people.
On Tuesday, Justice Harrison noted that in speaking to a psychologist, Yoo said the lies became bigger and bigger as his wife and students asked more questions.
However, he still failed to reach the success that he desired.
"You've been living your life as a good person for long enough. You can be a bad person and give your family whatever they want," the 51-year-old said.
The judge noted Yoo had been burdened since childhood with unrealistic expectations from his parents and culture about the level of success he needed to achieve.
At the time of his arrest, he owed tens of thousands of dollars in debt and was behind on rent.
Yoo was handed a box of tissues as Justice Harrison described his deep remorse for the hurt and pain that he had caused.
In a letter to the judge, Yoo said he was "held captive by sin" and that he wanted to give himself to Jesus Christ.
“I wish I could turn back time so this didn't happen," he wrote.
"I pray every day for the people I have hurt.”
The victims cannot be identified due to NSW legal restrictions on identifying child victims of crime.
