Murder of Li Sin-heng

On 16 September 2017, at around 4 p.m., 20-year-old Annie Li Sin-heng, a year-three nursing student at Hong Kong Polytechnic University (PolyU), was stabbed to death by her boyfriend, Ng Yan-kin, aboard a Citybus Cross-Harbour route 118 bus traveling along Chai Wan Road in Hong Kong. Ng, then 22, had recently graduated from PolyU with a civil engineering degree and had begun working as an engineer in Ho Man Tin earlier that year.

Li and Ng had been dating for about a year. Ng reportedly described Li in positive terms, but Li viewed him as a possessive partner who grew jealous when she was around other men. In the early hours of the day of the killing, the couple argued over several issues, including the destruction of intimate video clips, and Li told Ng she was ending the relationship.

The pair boarded the bus at Siu Sai Wan and sat at the rear of the upper deck. Witnesses described hearing whispering, followed by sounds of vomiting, before a passenger noticed Li coughing blood and alerted the driver that someone had been stabbed. Ng, holding the knife, stabbed himself in the chest and abdomen, warned other passengers away, then smashed a window with an emergency hammer and jumped from the moving bus onto the road below, losing consciousness. Li was found fatally wounded on the upper deck. She was taken to Pamela Youde Nethersole Eastern Hospital, where she died from her injuries despite CPR performed en route. Ng, severely injured from the fall, was also taken to Eastern Hospital and underwent surgery before being placed in intensive care.

Police treated the case as a murder connected to a relationship dispute and arrested Ng shortly after the incident. Detectives recovered the knife and other evidence at the scene. Citybus cooperated with the investigation, later cleaning and repairing the bus, which returned to service eight days later.

Ng's court hearings were repeatedly delayed due to his medical condition, with proceedings beginning in October 2017 and continuing through 2018. At trial in October 2020, Ng pleaded guilty to manslaughter but not guilty to murder, citing mental instability; prosecutors countered that he had purchased the knife at a shop before boarding the bus, indicating premeditation. On 8 December 2020, a jury convicted Ng of murder. On 29 April 2021, he was sentenced to life imprisonment, the mandatory sentence for murder in Hong Kong.