The suspect, 29-year-old Kwan Cin Cheng (关进清 Guān Jìnqīng), who was a Perak-born Malaysian working in Singapore, was charged with murder.
This appeal later became a landmark in Singaporean legal history in relation to the requirements of successfully raising a defence of sudden and grave provocation against a murder charge in Singapore.
[3] Throughout the suicide attempts, the police had responded to a report of the stabbing and around 70 officers were deployed to conduct a manhunt for Phang's ex-boyfriend.
[18][2][19] On 11 April 1997, six months after the murder of Phang Ai Looi, 29-year-old Kwan Cin Cheng stood trial at the High Court for the crime.
Kwan was represented by Chua Eng Hui and Leo Cheng Suan, while the prosecution consisted of Christina Koh and Jasbendar Kaur.
Kwan's testimony revealed that on the night of 4 October 1996, he was in despair over Phang's decision to break up with him and her unfaithfulness, and he went to a supermarket, purchasing two knives, and wanted to kill himself.
He contacted Phang under the pretext of returning some money to her, and they met up at a carpark below Kwan's flat in Yung Kwang Road.
The prosecution sought to impeach the defence of sudden and grave provocation, claiming that since the couple were not married and Phang herself already expressed her intention to break-up with Kwan some time prior to the killing, Kwan could not have been sufficiently provoked into killing Phang solely based on her verbal remarks, and he should be found guilty of murder.
He further found that the provocation from Phang caused Kwan to use the knife to kill her in a spontaneous moment of uncontrollable anger.
[25][26] According to the media, Kwan, who celebrated his 30th birthday sometime during the trial, was relieved and he broke down in tears before the prison officers escorted him out of the courtroom.
Kwan's lawyer Chua Eng Hui also commented that for having killed the person he loved dearly, his client had paid a very heavy price and would have to live with that fact for the rest of his life.
Phang's 24-year-old elder sister was saddened to hear the judgement and refused to speak to reporters as she left the courtroom in tears.
[27] A month after Kwan's sentencing, psychiatrists and counsellors were interviewed with regards to the increasing occurrences of crimes of passion, including murder that involved people killing their spouses, lovers or others close to them.
They told the papers that crimes of passion were not premeditated or cold-blooded murders because they happened in a spontaneous spur of moment and the killers losing self-control.
Experts also emphasized that crimes of passion, including the murder of Phang, were committed due to the offenders being triggered by words or actions that caused them to be uncontrollably angry, and the offenders of such cases had no intent to cause death or harm; the motive was often due to infidelity, love or possessiveness rather than any premeditated intent to commit these crimes.
In the verdict, the three judges unanimously ruled that the prosecution's appeal ought to be rejected, while they decided to increase Kwan's jail term of ten years to life imprisonment.
Therefore, they decided to enhance Kwan's sentence to life imprisonment, the highest punishment stipulated for manslaughter under Singaporean law.
Since Kwan committed manslaughter on 4 October 1996, about ten months before the landmark appeal verdict, his life sentence was to be considered as 20 years' imprisonment.