Man arrested as new details revealed over death of mum, dad, boy

Police are investigating whether the bodies of a woman and a seven-year-old boy discovered at a Sydney taekwondo studio and her estranged husband nearby are linked to a love triangle.

A taekwondo instructor has been arrested after police allege he strangled a woman and a young boy until they died inside a Western Sydney martial arts studio before confronting the woman’s husband at a nearby home and stabbing him to death.

Authorities were first alerted to the situation after taekwondo instructor Kwang Kyung Yoo, 49, presented to Westmead Hospital late on Monday night with injuries to his arms.

A series of grim discoveries would lead NSW Police to the bodies of Steven Cho, 39, then his wife Min Cho, 41, and a seven year-old boy at two different locations in Western Sydney on Tuesday.

Mr Yoo – known in sporting circles as Master Lion – was arrested at Westmead Hospital on Tuesday night and remains in hospital after having surgery for the non life-threatening injuries. He is reportedly a married father-of-two from North Kellyville who faked a university professorship on social media.

Kwang Kyung Yoo has been arrested.

Detective Superintendent Danny Doherty confirmed the arrest on Wednesday and charges are expected to be laid.

“Following extensive inquiries, about 11.20pm last night, Strike Force detectives attended Westmead Hospital where the 49-year-old man was placed under arrest. The man remains under police guard in hospital receiving treatment for his injuries and is expected to be charged at some stage,” he said.

“What we will allege is the 49-year-old is the only person responsible and we’ll allege that he’s responsible for the murder of all three victims.”

Police will allege the mother and small child were strangled inside the martial arts centre between 5.30pm and 6.30pm on February 19.

“What we’re going to allege is they were subjected to an assault. We’ll allege it was murderous intent and they died from their injuries,” Detective Superintendent Doherty said.

Steven and Min Cho.

Mr Yoo then drove Ms Cho’s white BMW to a Baulkham Hills home and confronted her husband Mr Cho, police will allege. “As a result of that confrontation he’s been stabbed to death,” the detective said.

He then drove himself to Westmead Hospital about 11.50pm and presented with stab and slash wounds to his chest, arms and stomach.

The next morning, police visited Mr Yoo in hospital where he told them he had been attacked in a carpark in North Parramatta. Police said they are yet to determine how he sustained those injuries.

“As a result of yesterday and with all the concern from welfare and how it unfolded, it set off a chain of events which I think is not only tragic in the circumstances, but the consequences are cataclysmic. We have just lost three people ... who had their lives taken away, or what we allege is a murder,” Detective Superintendent Doherty said.

The attack on the three people “was out of the blue”. Police were reportedly probing whether a relationship between Ms Cho and Mr Yoo turned sour, but on Wednesday Detective Superintendent Doherty said it was too early to speculate on a motive.

This one of the crime scenes in Daking Street North Parramatta where the bodies of the woman and child were discovered at a Taekwondo Martial Arts Academy. Picture: NCA NewsWire / Dylan Coker

Mr Cho worked as a senior estimator at Richard Crookes Constructions. His mother arrived at the Baulkham Hills home after police, where she was told the family had been killed.

The rest of the family is believed to be in South Korea and police said the consulate was helping authorities reach them.

Black sheets of plastic covered the windows of the studio on Wednesday morning as investigators continued to scour the area to piece together what occurred, asking nearby businesses for CCTV footage.

Taekwondo classes were held until 8pm on Monday evening, with homicide detectives believing the deaths took place in the five hour window between then and Mr Yoo’s hospital arrival at 1am Tuesday.

The scene outside Lion’s Taekwondo in North Parramatta. Picture: NCA NewsWire / Dylan Coker

Students at the studio were reportedly sent text messages on Tuesday that said classes had been cancelled as Master Lion has been in a car accident.

“Due to injuries resulting from a car accident this morning, Master is currently in the hospital. Therefore, taekwondo classes will be temporarily suspended starting today,” the message said.

But some school kids arrived with their parents at 3:30pm to see the area teeming with police.