Armed robbery On the morning of 23 July 1983, at around 8 am, 10-year-old Dawn Jacinta Tay Aishan (), the youngest daughter of 61-year-old retired businessman Robert Tay Bak Hong (), was
roller-skating outside her house while waiting for her Mandarin tutor, Madam Tang So Ha () to arrive to give her lessons. At around the same time, two houses away, two young men were fixing their motorcycle. The tutor arrived at the house thirty minutes later. Forty minutes after the arrival of Dawn's tutor, the two men seen repairing the motorcycle - 19-year-olds
National Serviceman Sek Kim Wah and
Malaysian Nyu Kok Meng - saw the front gate of Dawn's bungalow left open. They took out a loaded
M16 rifle (which Sek had stolen from
Nee Soon military camp where he served his
National Service) and brandished a knife before barging into the bungalow, first taking the Tay family's
Filipino domestic helper Jovita Sandrina Virador (nicknamed Duby, also spelled Jovita Merador, Jovita Verador, Jovita Verazor or Jovita Mirador), aged 27, hostage. They entered the house with Jovita and used the rifle to threaten Dawn, Tang, and Dawn's 40 or 45-year-old mother Annie Low Au Ie (), forcing them inside a room before tying them up. One of the men forced Dawn to call her father, who was in the back garden; Robert Tay was lured into the room and tied up as well. After telling Sek where to find her jewelry, Low was told to write a cheque for $5000, which was immediately taken by Sek to the bank to cash while Nyu stayed behind to guard the hostages. Feeling sorry for the tutor, whose head was covered in a plastic bag, he removed it for her. Sek returned with the money but was not satisfied with the loot they had, so he took Tay to the bank with him to withdraw more cash. During the time Sek was out with Tay, Nyu told the women that he would not harm them, as it was his first robbery and he had no intention to harm anyone. At the request of Low, Nyu shook hands with Dawn as a promise to not hurt them.
Triple murder Sek later returned with $7,000. After gagging the victims and taking Tay, Low, and Jovita into separate rooms, the robbers continued to ransack the house. Afraid of leaving behind witnesses, Sek secretly decided to murder all the hostages. He first used a
raffia string to strangle Tay, before using a wooden stool to repeatedly bludgeon him until he was dead, fracturing his skull. He entered the master bedroom, where he strangled Jovita and Low, again using a wooden stool to repeatedly strike Low's covered head. After being alerted by the thumping sounds in the house and witnessing Sek's actions, Nyu armed himself with the rifle and locked himself in the room with Dawn and her tutor, intending to protect the surviving hostages. Sek later returned to the room where Nyu, Dawn, and Tang were hiding and demanded that Nyu let him in to murder the remaining hostages, actually intending to also kill Nyu. Nyu adamantly refused and asked Sek why would he commit murder when he had already robbed the victims of their money, and told Sek to leave. After a heated row between the two men, Sek left the house in Tay's
Mercedes car with the loot. Nyu then released both Dawn and Tang and told them to run away, informing them of the murder of Dawn's parents and maid and furnishing them with Sek's address. He drew a map of the area where Sek lived in on an envelope and gave it to Tang, who was afraid that Nyu still might harm her and her student and secretly armed herself with a small knife. Nyu also gave her his Malaysian
identity card, telling her to help him buy a coffin and inform his parents and grandmother that he was sorry, as he wanted to commit suicide. He also asked Tang to bury him next to his deceased best friend Lau Beng Hiong (), whose Chinese name he wrote inside Dawn's exercise book before giving it to her. Nyu wanted her to repeat his requests, and despite her fear of Nyu, Tang tried to dissuade Nyu from committing suicide. It was only when Nyu pointed the rifle at her that Tang fled the house with Dawn (who saw her parents' bodies) to a neighbour's house to contact the police. Nyu tried to shoot himself twice, but failed, as he did not know how to use the rifle. Frustrated, Nyu fled the bungalow, but not before leaving behind the rifle and stolen ammunition, for fear that Sek would murder more people. He met up with Sek in another safe place that afternoon to divide the loot. Nyu later left Singapore on that night itself for Malaysia using a friend's passport, while Sek remained in Singapore.
Arrests Meanwhile, the police arrived at the bungalow and searched the house for the robbers, but they could only find the bodies. The case was assigned to Inspector
P. Sathasivam of the
Criminal Investigation Department. The police knew that Tay, a father of eight adult children (including one foster son) and a grandfather of five grandchildren, had a reputation of being a generous and virtuous businessman who had helped ex-convicts to reintegrate into society by providing them work at the factory, hence they ruled out the possibility of a revenge killing. With Nyu's Malaysian identity card and the map drawn by Nyu, the police managed to arrest Sek six days later at his elder sister Sek Yoke Mui's flat on 29 July 1983. Unable to cope with his guilt, Nyu surrendered himself to the police three days after Sek's arrest and was extradited back to Singapore on 3 August 1983. Both men were charged with murder. ==Background of the robbers==