Velusamy's killer was arrested a week after his death, when 26-year-old labourer Ismail bin U. K. Abdul Rahman was caught as a suspect.
Ismail, who earlier confessed to committing the murder due to a misunderstanding between him and the victim, denied in court that he was the perpetrator and claimed an alibi, stating he was sleeping at his girlfriend's home at the time of the offence.
Velusamy's death was believed to be caused by a group of men armed with deadly weapons, based on speculations and theories that the police considered during investigations.
[4][5][6] Professor Chao Tzee Cheng, a senior forensic pathologist, conducted a post-mortem examination on Velusamy, and based on his autopsy findings, Professor Chao found that Velusamy sustained traumatic head injuries, and two major fractures (measured 4 cm and 6 cm respectively) were located on the lower side of his skull; another two skull fractures were inflicted below his right eye, and these injuries were sufficient in the ordinary course of nature to cause death.
[10][11] On 8 October 1973, the suspect, identified as 26-year-old Ismail bin U. K. Abdul Rahman, was officially brought to trial at the High Court for murdering Karuppan Velusamy.
Another key witness for the prosecution was Mohammed Micha, who testified that on the day of the murder, after the crime was committed, Ismail had admitted to him that he had beaten Velusamy and caused his death.
Prior to 2013, the death penalty was classified as the mandatory sentence for all four degrees of murder under the Singaporean Penal Code.
[32] As a final recourse to escape the gallows, Ismail petitioned to the President of Singapore for clemency, with hopes to commute his death sentence to life in prison.
[34][35] The case, known as the Gold Bars triple murders, was committed by the seven condemned and three other accomplices, two of whom were minors and thus imprisoned at the President's Pleasure rather than facing execution; a third man turned state evidence against the nine others and was detained indefinitely without trial under the Criminal Law (Temporary Provisions) Act.