On 13 March 2016, at their flat in Compassvale Crescent, Seng Kang, Singapore, 63-year-old Wong Chik Yeok (黄池玉 Huáng Chíyù) was slashed and stabbed to death by her 68-year-old husband Kong Peng Yee (江炳义 Jiāng Bǐngyì) with a cleaver and knife.

[9] During preliminary investigations, the police were unable to find a motive, given that Wong's family was harmonious and close-knit and there were no known conflicts arising between them, and the couple's two daughters (who both worked as teachers) were filial and obedient.

Additionally, Kong exhibited strange behaviour and he appeared troubled, telling his older daughter to care for her sister if he was no longer alive.

Wong put up a struggle with her husband, who dropped the knife, but Kong was undeterred, and he returned to the kitchen to grab a cleaver and started hacking his wife until she died.

Dr Chan certified in her report that Wong had died as a result of massive blood loss from the multiple incised wounds on her head.

Kong's daughters, who called the police, rushed back home and found their father sitting on the sofa and their mother lying in a pool of blood.

[24] On 8 September 2017, Kong , who was then 69 years old, stood trial at the High Court before Justice Choo Han Teck for the killing of Wong.

The psychiatric reports from Dr Kenneth Koh certified that Kong was suffering from diminished responsibility as a result of his psychotic delusions.

They argued that Kong had acted with "senseless brutality" and callously snuffed out the life of his wife, who was utterly defenceless against her husband, who was "relatively unscathed by the savage attack while she suffered a colossal 189 injuries", and a harsh and deterrent sentence was called for in view of the circumstances.

They urged the court to consider that in spite of the importance of protecting the public and retribution, Kong's psychiatric condition was the direct cause of his actions, and he was in remission due to consistent treatment behind bars.

Justice Choo stated that language of the M'Naghten rules should be re-examined, because with the application of the M'Naghten rules, "legal insanity and medical insanity have not fitted themselves snugly in the same box" and it disregarded the fact that there were multiple varieties of mental illnesses which could lead to an abnormality of mind, and the extent of impairment of the mental faculties were not the same for all illnesses.

They stated that the two-year prison term should not be upheld, as it would be a case where the ends of justice was not fulfilled despite the extremely brutal and vicious manner of Wong Chik Yeok's death.

Also, after Kong was released in October 2017, he did not return home and instead voluntarily admitted himself as a patient at the Institute of Mental Health (IMH) where he continued to accept treatment.

[40] The Court of Appeal adjourned their decision to a later date after indicating they needed more time to look through further psychiatric evidence to determine the degree of prospects of recovery and possible risks of a relapse in Kong's case.

[42] Justice Tay also disagreed with the prosecution that the principles of deterrence and retribution should be prioritized when deciding on Kong's sentence, as they found this principle "should not be a dominant consideration" during sentencing, given that the psychosis was "causally linked to the offence and warped his understanding of reality", and the emphasis on retribution should not be as high, because in spite of Kong's merciless and violent attack on his wife, the brutality of the killing arose from the workings of a "disordered mind rather than a cold and cruel one".

However, the first and second options were not chosen, because for the first choice, it was unsatisfactory due to Kong having the freedom to leave IMH on his own accord and there would be no assurance that he would continue to take his medication.

The second was not chosen because probation was generally reserved for less serious offences and aimed to fulfill the purpose of rehabilitating young offenders in need of guidance and discipline.

[44][42] After due consideration, the appellate court decided that Kong should be incarcerated for a longer period than two years, and his sentence should be increased for the sake of public interest.