However, in January 1992, Ithinin was found guilty of murdering both Mohd Said and Mohamed Johar, and sentenced to death, due to his actions being grossly out of proportion to the provocation given.

Mohamed Johar, a primary school drop-out who was 33 years old at the time of his death, was a technician with an offshore oil company and the second child out of seven in his family.

Mohd Said was a 29-year-old machinist employed by a Jurong oil tools company and the third child out of a family of nine, and he formerly studied at Tun Seri Lanang Secondary School.

[6] One of the neighbours, Alice Phua, told the press that she heard a woman screaming and shouts from several men, and saw one of the victims lying outside her flat in a pool of blood.

[7][8] On 2 June 1989, the police apprehended the Tanglin Halt double killer for causing the deaths of Mohamed Johar and Mohd Said after they established his identity.

[12][13] On 6 January 1992, Ithinin Kamari stood trial at the High Court for two counts of murdering Mohd Said Abdul Majid and Mohamed Johar Selamat.

According to Zainuddin, he told the court during the defence's cross-examination that Mohd Said had uttered "kurang ajar", which meant ill-mannered in Malay and sounded offensive.

After being kicked by the men after the abusive language, Ithinin became very angry and entered the flat to grab a knife, and stabbed both Mohamed Johar and Mohd Said.

Having rejected the defence of sudden and grave provocation, as well as finding that Ithinin had the intention to kill and/or cause the fatal wounds to Mohamed Johar and Mohd Said, the judges concluded that there were sufficient grounds to return a verdict of murder.

They also stated that Ithinin had inflicted lethal wounds on the vital parts of both Johar and Mohd Said's bodies, which was not justifiable, and was excessive violence for a person acting under a grave and sudden provocation.

In this case, which ended with Kwan serving a life sentence for manslaughter, the Court of Appeal re-affirmed that based on the mental background of the accused and the "reasonable man test", the defence of sudden and grave provocation could still succeed if verbal remarks could result in one losing his self-control and killing the victim in a fit of uncontrollable anger, which the court accepted in Kwan's case.

One of these cases was the 1999 trial of Lau Lee Peng, a fishmonger charged with murdering his friend and fruit stall helper Tan Eng Yan.