On the morning of 2 November 1970, at a bungalow house at Leedon Park, 14-year-old schoolgirl Low Ek Meng was the first to discover her mother being murdered.

Wu, who was a Hainanese-born Singaporean, was working as an amah for the bungalow's owner C P Thomas, who was absent from his home and on holiday with his whole family at the time of the murder.

The suspect was 31-year-old Osman bin Ali, a gardener who worked for the bungalow's owner, and was a colleague of the two victims Tan Tai Hin and Wu Tee.

[8][9] Prior to the murders, Osman was said to share a good relationship with both his alleged victims Tan and Wu, and had worked for the household for ten years.

[12] On 14 September 1971, after a five-day preliminary hearing in February of the same year,[13][14] 32-year-old Osman bin Ali officially stood trial at the High Court for two charges of murdering Wu Tee and Tan Tai Hin.

Osman told the court that he suffered from head injuries due to a traffic accident ten years ago, and hence he became easily prone to anger and fought with his sisters and step-brothers.

Marshall sought to argue that these above factors, be it mental or environmental, had been sufficient to prove that Osman was suffering from an abnormality of the mind and therefore, he should not be guilty of murder but of manslaughter.

[24][25] However, Dr F Y Long, the prosecution's psychiatric expert, testified that despite his low IQ, Osman was observed to be spontaneous, relevant, clear of speech, rational and co-operative.

In the judgement, Justice Singh, who pronounced the verdict, stated that the prosecution had proven its case beyond a reasonable doubt, accepting the evidence that Osman was not suffering from any abnormality of the mind when he killed both Tan Tai Hin and Wu Tee, and hence, they found 32-year-old Osman bin Ali guilty of committing the premeditated murders of Tan and Wu, and sentenced him to death for two counts of murder.

[29][30] Reportedly, Osman's 48-year-old mother Che Maria binte Supri, who had been fasting and praying for her son, was so distraught at the death sentence that she actually fainted, and had to be brought out and laid on a bench until she regained consciousness.

[33][34] However, on 11 September 1972, the three judges - Supreme Court judges Tan Ah Tah and F A Chua, and Chief Justice Wee Chong Jin - found that there were sufficient evidence to demonstrate that Osman indeed never suffered from diminished responsibility at the time of the murders, and therefore dismissed the appeal on the basis that Osman had indeed committed the murders with the intention and premeditation to cause death.

[35][36][37] In February 1973, Osman was revealed to be one of the eleven inmates on death row awaiting their executions, among them included Mimi Wong, Sim Woh Kum, the seven Gold Bar killers, and labourer Chow Kim Hoong, and they were all convicted of murder.