Doctor used yoga ball filled with gas to kill wife, daughter, prosecutors say

( - An anesthesiologist used a yoga ball filled with carbon monoxide to kill his wife and daughter in 2015, prosecutors told a Hong Kong court Wednesday.

Khaw Kim-sun allegedly left the exercise ball filled with the gas in a locked car with the two women, where it slowly leaked carbon monoxide and killed his wife and 16-year-old daughter, the BBC reported. Khaw pleaded not guilty to “two counts of murder.”

An autopsy determined the doctor’s wife and daughter died from carbon monoxide poisoning. While investigating, police discovered a deflated yoga ball in the car near where the two bodies were found. The South China Morning Post reported a jogger found the bodies in the parked car.

Khaw, who was an associate professor at the Chinese University of Hong Kong, allegedly killed his wife because he was having an affair with a student and his wife wouldn’t divorce him, prosecutors told Hong Kong’s High Court, according to Sky News.

Witnesses reportedly said they saw Khaw filling exercise balls with carbon monoxide. The professor told colleagues he was using the gas to kill rabbits, however, he allegedly contradicted his statement when speaking to the police, saying he was using the carbon monoxide to kill rats in his residence.

Khaw reportedly obtained the carbon monoxide from the teaching hospital where he worked, and was assisted by the student with whom he was having an affair. He told colleagues he wanted to "test its purity" and its effects on rabbits, the paper said.

It said that later, he told police he'd wanted to use it to exterminate rats at home, although a domestic helper employed by the family testified that they had no rodent problem.

Khaw was unaware his daughter was home from school on the day of her death and likely had not intended to kill her, the paper quoted prosecutor Andrew Bruce as saying.

"The last thing the accused wanted was for his 16-year-old to die," Bruce was quoted as saying.

"(But) if that person knew what was in the car was carbon monoxide and knew it was a dangerous gas likely to kill you, you can confirm this person had homicide on his mind," Bruce was quoted as telling the jury of five men and four women.

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