A taekwondo instructor in Sydney who murdered his seven-year-old student and both parents was consumed by elaborate fantasies of Olympic glory and billionaire encounters, a court has heard.
The Gruesome Family Murder
Kwang Kyung Yoo, 51, pleaded guilty to killing the young boy and his parents in February 2024, with prosecutors arguing he should never be released from prison. The New South Wales Supreme Court will deliver his sentence on 16 December.
Under state law, child victims of crime cannot be identified, meaning the names of his parents also remain protected. All four individuals involved in the tragedy were born in South Korea.
A Life Built on Fantasies
Evidence presented to the court revealed Yoo had constructed an elaborate fantasy life, claiming he had met Australia's wealthiest person Gina Rinehart, qualified for the Sydney Olympics, and owned a Lamborghini.
Forensic psychiatrist Andrew Ellis told the court: "These are a form of fantasy, essentially a grandiose or self-important fantasy that he's richer, has more social status, has more success in life in different domains than he actually does."
In a particularly revealing detail, Yoo would send emails to himself pretending to be important people to impress his wife, sometimes signing them as "professor Yoo".
From Envy to Murder
Prosecutors stated that Yoo's murderous intentions emerged after he witnessed the success and wealth of his student's father. The court heard how Yoo began plotting to kill the family to obtain their money.
The horrific events unfolded after a class at the Lion's Taekwondo and Martial Arts Academy, where Yoo was behind on rent and struggling with debt. He strangled the mother and son at his academy before driving the woman's BMW to the family home, where he fatally stabbed the father.
During the struggle, the father managed to stab Yoo, who then drove himself to hospital claiming he'd been attacked in a supermarket car park. Police arrested him at the hospital the following day.
After his arrest, Yoo expressed remorse to prison authorities, stating: "I was ... good ... two months ago. Now I'm a murderer. I feel shame, guilt and sorrow."
Sentencing Arguments
Yoo's lawyer Richard Wilson contested the prosecution's claim that his client was motivated by "jealousy and hatred", arguing instead that while there was evidence of envy, it wasn't the primary motivator.
Wilson requested that Yoo be given a minimum non-parole period rather than life imprisonment without possibility of release. Under New South Wales law, the maximum penalty for murder is life imprisonment, with standard non-parole periods of 20 years for adult murder and 25 years for child murder.
