A Hong Kong appellate court has quashed the murder conviction of a jobless man who allegedly beat his girlfriend to death and hid her body under a mattress seven years ago, ruling that the trial judge had not properly directed the jury to fully consider the alleged perpetrator’s violent personality traits.

The Court of Appeal on Thursday ruled in favour of Law Wai-man, who was found guilty of murdering his girlfriend Lau Lee-chi in 2019, overturning his conviction and ordering a retrial.

Law, now in his mid-50s, argued in the 2022 High Court trial that he was provoked into beating his then 34-year-old girlfriend after the two had been quarrelling for a few days in 2019. Lau was found dead in a public housing flat in Tseung Kwan O on or around March 17, 2019.

The trial revealed that Law had a long history of drug abuse and was easily provoked when he increased his use of methamphetamine, known as Ice. He admitted that he was agitated at the time of the killing as he had taken a higher dose of the drug.

Law told police he had bound his girlfriend with a cloth beside a window after she began displaying hysterical behaviour two to three days before the killing. She was also a drug user.

He said he had punched and kicked her in the early hours of March 17, fearing her yelling would alert neighbours.