Toa Payoh ritual murders

On 25 January 1981, the body of nine-year-old Agnes Ng Siew Heok was found stuffed in a travel bag at a Toa Payoh public housing block, hours after she disappeared from a church where she attended Bible classes. She had been suffocated, and forensic examination found injuries consistent with sexual assault. Two weeks later, on 7 February 1981, the body of ten-year-old Ghazali bin Marzuki was found under a tree nearby; he had been missing since the previous day after being seen entering a taxi with an unidentified woman. He had drowned, and showed suffocation marks, burns, and a puncture wound, with sedative traces found in his blood.

A trail of blood led police to a seventh-floor flat in a neighbouring block occupied by Adrian Lim, a self-styled spirit medium, his wife Catherine Tan Mui Choo, and a woman named Hoe Kah Hong whom Lim called his "holy wife." Police found blood traces, slips of paper bearing the victims' personal details, and hair later matched to Agnes Ng. All three were arrested and subsequently charged with murder.

According to the Wikipedia account of the case, Lim had for years operated as a fraudulent healer who sexually assaulted and financially exploited female clients, and had subjected Tan and Hoe to prolonged physical, sexual, and psychological abuse. In late 1980, Lim was charged with the rape of a saleswoman, Lucy Lau Kok Huang. To distract police investigating that case, Lim decided to kill children, believing sacrifices to the Hindu goddess Kali would help him escape prosecution; he also sexually assaulted the girl victim. Tan and Hoe were reportedly compelled by Lim to assist in identifying, drugging, and killing both children.

The trial opened at Singapore's High Court on 25 March 1983 and ran 41 days, at the time the second-longest trial in Singapore's courts. None of the three defendants disputed that they had killed the children; their defence counsel argued diminished responsibility, presenting psychiatric evidence that the defendants suffered from schizophrenia or psychotic/manic depression. The prosecution's psychiatric expert argued that all three were in full control of their faculties. On 25 May 1983, Justices T. S. Sinnathuray and Frederick Arthur Chua rejected the diminished-responsibility defence and convicted all three of murder, imposing the then-mandatory death sentence. Appeals by Tan and Hoe to the Court of Criminal Appeal, the Privy Council in London, and for presidential clemency were unsuccessful; Lim did not appeal. All three were executed by hanging at Changi Prison on 25 November 1988.

The case drew intense public and media attention in Singapore for years afterward, inspired two feature films in the 1990s and a planned television re-enactment episode, and became a case study in Singapore law on the diminished-responsibility defence.