Taekwondo Instructor’s Dark Fantasies Exposed After Horrifying Triple Murder

A Sydney taekwondo instructor who murdered a family of three was reportedly driven by elaborate fantasies of fame, wealth, and power, a court heard Thursday.

Prosecutors said 51-year-old Kwang Kyung Yoo, who has pleaded guilty to killing a seven-year-old student and the child’s parents last February, should never be released from prison. A Supreme Court judge in New South Wales is expected to hand down the sentence on December 16.

Because the law protects the identity of child victims, the young student and his parents cannot be named. All four individuals, including Yoo, were originally from South Korea.

In court, prosecutors revealed that Yoo created an entire fictional world around himself. He falsely claimed he had met Australian billionaire Gina Rinehart, qualified for the Sydney Olympics, and owned a Lamborghini. He even emailed himself pretending to be high-profile figures in an attempt to impress his wife, sometimes signing off as professor Yoo.

Forensic psychiatrist Andrew Ellis described these behaviors as grandiose fantasies designed to inflate Yoo’s sense of importance. In reality, Yoo was drowning in debt and behind on rent at the Lion’s Taekwondo and Martial Arts Academy—the same place where he murdered the mother and her son after a class.

Prosecutors say Yoo began thinking about killing the family after watching the student’s father become successful. His fixation shifted to how he might steal their wealth.

Investigators say Yoo strangled the mother and child inside the academy, then drove the woman’s BMW to the family home, where he fatally stabbed the father. During the struggle, the father managed to stab Yoo as well. Yoo then drove himself to a hospital and falsely claimed he had been attacked in a supermarket parking lot. Police arrested him the following day.

Following his arrest, Yoo reportedly struggled to explain how he intended to access the family’s money, and later expressed remorse, telling authorities, “I was good two months ago. Now I’m a murderer. I feel shame, guilt and sorrow.”

Defense lawyer Richard Wilson pushed back against prosecutors’ claims that jealousy and hatred drove Yoo’s actions. According to Wilson, while Yoo may have envied the family’s success, there was no evidence of deeper malice. He argued that Yoo should receive a minimum non-parole term rather than life without the possibility of release.

In New South Wales, the maximum penalty for murder is life imprisonment, with standard non-parole periods of 20 years for an adult victim and 25 years for a child.