Liang was found dead nearly two weeks later at Yishun Industrial Park, where her highly decomposed body was discovered by a group of National Servicemen who were training nearby that area.

Despite conducting a post-mortem examination, the cause of Liang's death was uncertain due to the high state of decomposition and disappearance of certain body parts.

[1] The school bus driver, 34-year-old Oh Laye Koh (Chinese: 胡立国; pinyin: Hú Lìguó), was arrested as a suspect for Liang's alleged murder, solely based on circumstantial evidence against him.

After 3:00 PM, Liang's mother, Quek Meng Ghet, still did not see her daughter return home to their Balestier Road flat.

Liang's parents stated that their eldest daughter was normally obedient and had no hobbies, and she only hung out with her female friends outdoors.

The police were contacted, and the investigation team, together with forensic pathologist Chao Tzee Cheng, arrived at the scene.

Professor Chao could not tell whether it was a suicide, murder or accident due to the highly-advanced state of decomposition and the fact that some body parts were missing.

The school bus driver was identified as Oh Laye Koh, a 34-year-old Singaporean who was married with one son and resided at Ang Mo Kio.

Norhayah, who was stabbed several times in the throat, was also originally reported missing under similar circumstances as Liang and a coroner's court in 1984 issued a verdict of murder by person(s) unknown.

[24][25] On 22 October 1989, the skeletal remains of Liang were returned to the family for cremation and funeral preparations after Professor Chao completed the post-mortem examination.

This alibi was first presented to Liang's father when he suspected and confronted Oh during the twelve days before the discovery of his daughter's corpse.

[5] However, the mechanic, Tan Eng Dee, testified in court that Oh did go to his workshop on that day to repair his school bus, but he came at 9:00 AM instead of 1:00 PM.

[31] On 11 September 1992, 37-year-old Oh Laye Koh was acquitted of Liang's murder, as the trial judge Amarjeet Singh found insufficient evidence against him.

Given that there was only circumstantial, but no direct, evidence linking Oh to the death of Liang in the prosecution's case, Singh decided to not let Oh come to the stand to give his defence and granted him a discharge amounting to an acquittal.

[34] Oh Laye Koh also remained in remand behind bars to be investigated and face another trial for the second murder charge relating to the 1982 death of Norhayah binti Mohamed Ali while the prosecution's appeal to overturn his acquittal was pending.

[35] Liang's father was also distressed at the acquittal and wrote petitions to the Attorney-General's Chambers and the Government of Singapore, including one to then Senior Minister Lee Kuan Yew and then Prime Minister Goh Chok Tong to seek a review of his daughter's case.

He also accepted the prosecution's arguments and determined that none of the circumstantial evidence was able to show explanatory signs of Oh's supposed innocence after the review of the whole case.

He stated the failure of the prosecution to prove the cause of death or exact crime was not a reason to find Oh not guilty.

[44] Oh's conviction based on the exercise of the right to remain silent and circumstantial evidence was also widely reported and reviewed by many lawyers who paid attention to the case and its unusual nature.

[45] Oh's case was also the second conviction of murder secured solely based on circumstantial evidence in Singapore's legal history, after the high-profile Sunny Ang case back in 1965, in which Ang was convicted of his girlfriend Jenny Cheok's murder in the absence of the body, and also based on circumstantial evidence.

[52][53] Oh was reportedly angered at his failure to escape the death sentence and over ten of his family members (including his wife, who wept in court) and acquaintances were present to hear the verdict.

[57][58] His lawyer, Peter Fernando, who represented Oh during his appeal process, stated in a 2003 interview that Oh was one of his "most difficult clients", as he kept insisting his innocence and never showed any remorse for his crime even up till the moment of his hanging.