Wong's defence of diminished responsibility was rejected by the High Court, which found both herself and Sim guilty of Watanabe's murder and sentenced them to death, which also made them the first couple to be subjected to capital punishment in Singapore since its independence in 1965.

Her biological mother Leong Kuan Fong was so poor that she was unable to continue taking care of Wong, which led to her being sent to live with her father's first wife Ho Ah Soong and her nine half-siblings.

Wong, who possessed a bad temper since she was young, and with a family history of mental illnesses, was said to have frequently abused her husband, and would not hesitate to arm herself to physically assault Sim whenever their arguments turned violent.

Sim, who was a naturally mild-tempered person, often silently endured these physical abuses, which at one point left a scar on his forehead.

[3] Not only that, Sim himself was a compulsive gambler, who often gambled away their hard-earned money, which aggravated the family's already-precarious financial situation.

This forced Wong to take up part-time jobs to support their family, including a stint at a bar as a hostess.

Using her good looks and slender, sexually-attractive figure, Wong quickly earned popularity among the male customers of the bar.

In 1966, three years after she first started her bar hostess career, Wong first met Hiroshi Watanabe (渡边弘), an engineer and high-ranking member of a Japanese corporation.

[9] In late-1969, three years into his relationship with Mimi Wong, Hiroshi Watanabe decided to admit to his wife that he indeed had an affair with another woman.

Hiroshi could not end the relationship immediately, as he knew that Wong had a bad temper besides being able to drink a lot of alcohol.

On 23 December 1969, Hiroshi's wife Ayako Watanabe (渡辺 绫子) and her three children arrived in Singapore by flight.

Despite welcoming the family into the house and treating them nicely, Wong was writhing in jealousy behind this facade of kindness and politeness.

Despite her hatred and envy, Wong tried her best to be nice towards the family, and even offered sweets to Hiroshi's three children, who called her "Obasan" (which meant aunt in Japanese).

In fact, when she saw Hiroshi's loving and warm attitude with his wife and children, she could not bring herself to do anything to tear apart the family despite the jealousy.

[11] Wong went back to her estranged husband Sim Woh Kum, then aged 37, to tell him about her plans to kill Ayako.

Despite his own reservations about committing murder, Sim decided to accept the offer for he still loved Wong and he was facing huge financial troubles while alone taking care of his mother and two sons.

Wong brought along a pair of gloves and a knife, while Sim took a tin half-filled with toilet-cleaning liquid, in order to pretend to be a toilet cleaner coming to clean the house.

After hearing Wong telling her that she had brought a worker to repair a broken toilet basin, Ayako allowed them in.

He went inside the house and was shocked to see his three children crying over the corpse of his deceased wife, which sent the 37-year-old mechanical engineer into hysterics.

Wong and Sim were both identified out of an identification parade by Chieko, who would become the prosecution's key witness against the couple in their trial.

[22] Lawyers N C Goho and John Tan Chor Yong were assigned to represent Wong and Sim respectively in their defence.

Sim also lost his appeal on the same day, as the judges found that he, unlike what his lawyers argued, indeed shared a common intention with Wong to kill Ayako,[36] and he thus should be guilty of murder.

[37] Both Sim and Wong then filed for a special leave to appeal to the Judicial Committee of the Privy Council in London.

While she was appealing against her sentence and awaiting her execution, Wong continued to spend the remaining years of her life in solitary confinement at death row.

Jeleha added that, when such things happened, her husband Darshan Singh, who was also the prison complex's chief executioner, would step in to try to calm her down.

[42][43] On 27 July 1973, nearly three years and seven months after murdering Watanabe and five days after losing her plea for clemency, 34-year-old Mimi Wong and her 40-year-old husband Sim Woh Kum were both hanged at dawn, with executioner Darshan Singh carrying out the executions.

[47] In the aftermath of the case, both Mimi Wong and Sim Woh Kum were the first couple to be sentenced to death and executed in Singapore since its independence.

[54][55] In 1986, See Seow Beng, a 38-year-old housewife, was sentenced to death after being found guilty of killing a 61-year-old female sweeper Yap Soh Keow in 1983, due to the judges rejecting her defence of sudden and grave provocation.

Julaiha and two of the killers Chandran Rajagopal and Loganatha Venkatesan were executed in 2001, while the fourth fled Singapore till today and the fifth declining to help do the killing.

The controversial execution of Contemplacion despite her alleged innocence and mental disability caused deterioration in the diplomatic ties between Singapore and the Philippines within the next few years.