1981 series of murders and rapes in Singapore
The Toa Payoh ritual murders took place in Singapore in 1981. On 25 January, the body of a nine-year-old girl was found at a block of public housing flats in the town of Toa Payoh, and two weeks later, the body of a ten-year-old boy was found nearby.
The murders were masterminded by Adrian Lim, a self-styled healer who pretended to have supernatural powers and scammed people for years before the murders. He had also been sexually assaulting female clients, often preying on younger women from impoverished backgrounds. He married one such woman Tan Mui Choo and took on another woman Hoe Kah Hong as his "holy wife"—a term he used to manipulate women into having sex with him. Lim subjected them to extensive physical, mental and financial abuse, as well as sexual torture, for years before instigating the killings.
In 1980, Lim drugged and raped a woman who filed rape charges against him. To derail police investigations, Lim decided to kill children and also sexually assaulted the girl victim. The women were forced to assist him. The three of them were arrested after the police found a trail of blood leading from the body of the boy to their flat. Although the case name suggested ritualistic murders, the defendants said they did not conduct prayers, burning of joss sticks, ringing of bells, or any other rituals during the killings.
The 41-day trial was the second longest to have been held in the courts of Singapore at the time. None of the defendants denied their guilt. Their appointed counsels pleaded diminished responsibility, arguing that the accused were mentally ill and could not be held entirely responsible for the killings. Their experts, doctors and psychologists, analysed the defendants and concluded that they had exhibited schizophrenia, and depressions of the psychotic and manic order. The prosecution's expert, however, refuted testimonies and argued that all three individuals were in full control of their mental faculties when they planned and carried out the murders. The judges agreed with the prosecution's case and sentenced the trio to death. While on death row, the women appealed to the Privy Council in London and pleaded for clemency from the President of Singapore to no avail. Lim did not seek any pardons. The three were hanged on 25 November 1988.
Reports of the trio's deeds and the court proceedings were closely followed and remained prominent in the Singaporean consciousness for several years. Twice, movie companies tried to capitalise on the sensation generated by the murders by producing motion pictures based on the killings; critics panned both films for indulging in gratuitous sex and violence, and the movies performed poorly at the box office. The actions and behaviour of the three killers were studied by academics in the criminal psychology field, and the rulings set by the courts became local case studies for diminished responsibility.
The murders.
For several years Adrian Lim, a medium in Block 12, Toa Payoh Lorong 7, had been performing noisy rituals in the middle of the night. The residents complained several times to the authorities, but the rituals would always resume after a short time.
On the afternoon of 24 January 1981, nine-year-old Agnes Ng Siew Heok (), a student of Holy Innocents Chinese Girl School, disappeared. She was last seen by her sister and friend at a Toa Payoh church where she was attending religious classes. Hours later, the child was found in a bag outside a lift in Block 11, less than a kilometre (five-eighths of a mile) from the church. The girl had been smothered to death and the body was found naked. The investigation revealed injuries to her genitals and semen in her rectum. 
On 7 February, the body of ten-year-old Ghazali bin Marzuki, a student from Henry Park Primary School, was found under a tree between Blocks 10 and 11. He had been missing since the previous day, after being seen boarding a taxi with an unknown woman. Forensic pathologists on the scene deemed the cause of death as drowning, and found on the boy suffocation marks similar to those on Ng. Like Ng, his body was left naked. There were no signs of sexual assault. There were burns on the boy's back and a puncture on his arm. Traces of a sedative were later detected in his blood.
The police found a scattered trail of blood that led to the seventh floor of Block 12. Stepping into the common corridor from the stairwell, Inspector Pereira noticed an eclectic mix of religious symbols (a cross, a mirror, and a knife-blade) on the entrance of the first flat (unit number 467F). The owner of the flat, Adrian Lim, approached the inspector and introduced himself, informing Pereira that he was living there with his wife, Tan Mui Choo, and a girlfriend, Hoe Kah Hong. Permitted by Lim to search his flat, the police found traces of blood. Lim initially tried to pass the stains off as candle wax, but when challenged claimed they were chicken blood. After the police found slips of paper written with the dead children's personal details, Lim tried to allay suspicions by claiming that Ghazali had come to his flat seeking treatment for a bleeding nose. He removed hair from under a carpet and tried to flush it down the toilet, but the police stopped him; forensics later determined the hair to be Ng's. Requesting a background check on Lim, Pereira received word from local officers that the medium was currently involved in a rape investigation. Lim overheard them and became agitated, raising his voice at the law enforcers. Hoe also started getting agitated. Their actions further raised the investigators' suspicions that the trio were deeply involved in the murders. The police collected the evidence, sealed the flat as a crime scene, and took Lim and the two women in for questioning.
Perpetrators.
Adrian Lim.
Born on 6 January 1942, Adrian Lim () was the eldest son of a middle-income family. Described at the trial by his sister as a hot-tempered boy, he dropped out of Anglo-Chinese School. He worked in a variety of jobs, including as an informant for the Singapore government agency Internal Security Department.
In 1962, he joined the cable radio company Rediffusion Singapore where he worked for 14 years. For three years, he installed and serviced Rediffusion sets as an electrician before being promoted to bill collector. In April 1967, Lim married his childhood sweetheart with whom he had two children. He converted to Catholicism for his marriage. Lim and his family lived in rented rooms until his 1970 purchase of a three-room flat—a seventh floor unit (unit number 467F) of Block 12, Toa Payoh.
In 1973, Lim started part-time practice as a spirit medium. Lim usually preyed on vulnerable girls and women, often much younger than him, with little education and were from abusive or impoverished background. He rented a room where he attended to the women—most of whom were bargirls, dance hostesses, and prostitutes—introduced to him by his landlord. Lim's customers also included superstitious men and elderly women, whom he cheated only of cash. Lim continued these actions up until his arrest in 1981.
Lim had learned the trade from a bomoh called "Uncle Willie" and prayed to gods of various religions despite his Catholic baptism. The Hindu goddess Kali and "Phragann", which Lim described as a Siamese sex god, were among the spiritual entities he called on in his rituals. Lim deceived his clients with several confidence tricks; his most effective gimmick, known as the "needles and egg" trick, duped many to believe that he had supernatural abilities. After blackening needles with soot from a burning candle, Lim carefully inserted them into a raw egg and sealed the hole with powder. In his rituals, he passed the egg several times over his client while chanting and asked her to crack open the egg. Unaware that the egg had been tampered with, the client would be convinced by the sight of the black needles that evil spirits were harassing her.
Claiming he had supernatural powers to solve their problems through rituals, he used the pretext of a massage to sexually assault his female clients. He would have the woman strip together with him, and would massage her body — including her genitals — with Phragann's idol, and proceed to rape her. Lim's treatments also included an electro-shock therapy based on that used on mental patients. After placing his client's feet in a tub of water and attaching wires to her temples, Lim passed electricity through her. The shocks, he assured her, would cure headaches and drive away evil spirits. 
Lim used his fake powers to threaten and intimidate his female partners. He also used various types of abuse, such as isolation from family members and threats, to control the women and keep them trapped. Lim was extremely physically violent towards his partners; he would slam their heads against the wall, kick them and pull their hair. He also tortured them by electrocuting them. He coerced an 18-year-old student Christina Chong as well as Tan into prostitution. Between 1979 and 1981, he took about $120,000 from Chong after forcing her into the sex trade.
Tan Mui Choo.
Born in 1953 or 1954, Catherine Tan Mui Choo () was the eldest of four children. She was neglected by her parents who focused their attention on her brothers and sent her away at 13 years old to a vocational centre.
At 17 years old, Tan lost her grandmother, the only family member whom she was close to and was devoted to. Estranged from family, and young with little education and skills, the teenager started working at a bar to earn a living. 
At 20 years old, she was referred by a coworker to Lim for help with depression and other ailments. Tan started visiting him regularly. In 1975, Lim, then 33 years old, insisted that the 21-year-old moved into his flat, where he was then living with his then-wife and two children. The wife moved out with their children a few days later, and divorced Lim in 1976.
Lim quit his Rediffusion job and became a full-time medium. He enjoyed brisk business, at one point receiving S$6,000–7,000 (US$2,838–3,311) a month from a single client. 
In June 1977, Lim and Tan registered their marriage. Lim was extremely abusive towards Tan, regularly torturing her with electric shocks, beatings, threats, and lies. Lim sexually exploited and financially abused Tan: he forced her into becoming a prostitute and a stripper, and took her earnings. She went into further depression, experiencing suicidal thoughts and a sense of worthlessness. Lim made Tan convince young female clients to sleep with him.
Lim's torture extended to Tan's younger siblings. Lim forced Tan's younger sister into having sex with him and Tan, and forced the girl into prostitution too. Demanding Tan to have sex with younger males to preserve her youth, Lim pressured her into having sex with her 16-year-old brother regularly for over one year. He also forced her into having sex with another teenager.
Hoe Kah Hong.
Born on 10 September 1955, Hoe Kah Hong () was the third of six children. At eight years old, when her father died, she was sent away from family to Penang, Malaysia, to live with her aunt. She returned to the family at 15 years old, and worked as a seamstress, factory-hand and a production operator for Hewlett Packard.
In 1978, Hoe married Benson Loh Ngak Hua.
In 1979, her mother brought 24-year-old Hoe and her sisters to get treatment from Lim. Lim used his usual tricks to convince them that he had supernatural powers.
To make Hoe one of his "holy wives", Lim started isolating Hoe from her family through lies, intimidation and abuse. He made up an array of bewildering lies, claiming: she was an illegitimate child; her family were immoral people who practised infidelity; her husband Loh would force her into prostitution. Hoe eventually underwent a mock wedding with Lim who declared her as his "holy wife". Three months after first meeting Lim, Hoe moved in with him and Tan.
Loh sought out his wife at Lim's flat and Lim, under the pretext of asking Loh to observe Hoe getting treatment, murdered Loh. Lim convinced Loh to participate in an electro-shock therapy. Lim applied a large voltage to Loh, electrocuting him to death, while Hoe was stunned into unconsciousness. Loh was 25 years old.
Lim