Image copyright AFP Image caption As the verdict was read out, Mr Khaw (centre) shook his head and one of his children burst into tears

An anaesthetist has been jailed for life for killing his wife and 16-year-old daughter using a yoga ball filled with carbon monoxide in Hong Kong.

Prosecutors said Khaw Kim-sun, a Malaysian national, left the inflatable ball in the boot of a car where the gas leaked out and killed them in 2015.

Police were initially baffled when they found the pair dead inside the vehicle.

Mr Khaw denied the murders, and told police he had been planning to use the ball at home to get rid of rats.

After almost seven hours of deliberation, the jury of five men and four women reached a guilty verdict.

A post-mortem examination showed his wife and daughter had died from carbon monoxide poisoning. Police found a deflated yoga ball in the back of the yellow Mini Cooper in which their bodies were discovered.

Image copyright Getty Images Image caption There was a yoga ball in the boot of a locked car where Mr Khaw's wife and daughter were found dead

Prosecutors told Hong Kong's High Court that Mr Khaw had deliberately plotted to kill his wife because he was having an affair and she would not grant him a divorce, the South China Morning Post reported.

But they said it was unlikely he wanted to kill his daughter. He allegedly told his younger daughter to stay at home to complete her homework.

Eyewitnesses said they saw Mr Khaw, who is also an associate professor at Hong Kong's Chinese University, filling two balls with carbon monoxide, according to reports.

He told colleagues he was going to kill rabbits with the gas, but he contradicted himself by telling police he wanted to use it to get rid of rats at his home.

As the verdict was being read out, Mr Khaw shook his head and one of his three other children burst into tears.