A paranoid schizophrenic who stabbed to death a fellow cleaner after hallucinating that she had taunted him to kill her pleaded guilty to culpable homicide yesterday.
Pua Kok Heng, 57, who believes he is the victim of political persecution, attacked 62-year-old Madam Goh Ah Moy after she scolded him for using her equipment at Jurong East MRT station in November 2011.
Deputy Public Prosecutor Jasmine Chin-Sabado sought a life term for Pua, arguing that he poses a high risk of future violence to the community.
She also cited a psychiatrist's report in which colleagues had described him as a "nice guy" and a good worker.
Sentencing was adjourned to a later date as the High Court wanted clarification from psychiatrists on whether Pua requires lifelong treatment and why those with schizophrenia tend not to take their medication.
The court heard that Pua and two other cleaners were deployed to clean the MRT station on Nov 22, 2011. He did not have any cleaning equipment with him so he used mops and pails which belonged to Madam Goh.
When she later scolded Pua for dirtying her equipment, he became irritated and shouted at her to stop ranting before a fellow cleaner pulled him away.
The next morning, after he woke up, Pua heard voices and saw a "floating" image of Madam Goh challenging him to go to the MRT station with a knife.
He took a knife and confronted her there, shouting incoherently. His supervisor Simon Lim - who was shocked as he had thought of Pua as diligent and quiet - told him to calm down.
When Pua told him not to interfere and took out the knife, Mr Lim told him he was fired.
Pua continued shouting at Madam Goh until Mr Lim led her to safety.
The next morning, Pua again saw an image of Madam Goh "flying in" from the window and taunting him. This time, armed with two knives, he went looking for Madam Goh and stabbed her once in the chest with a 20cm blade, then pulled it out.
Pua was arrested that evening at his rental flat in Marsiling Road.
Dr Kenneth Koh from the Institute of Mental Health said Pua, who has been suffering from schizophrenia since 2002, had suffered a relapse at the time. The psychiatrist said Pua's persecutory delusions were "significantly causally linked" to his offence.
Yesterday, DPP Chin-Sabado argued that Pua should be jailed for life because he requires long- term psychiatric treatment. Pua has been known to stop going for follow-up treatment and has no familial support to ensure that he continues his treatment.
She argued that by the very nature of Pua's mental condition he is unstable and up until the day before the incident, people working with him did not notice any abnormal behaviour on his part.
Pua's lawyer Josephus Tan, who was representing him for free, asked for a jail term of not more than 20 years. He said that while in prison, Pua has been taking his medication and his condition has improved significantly.
This article was published on April 18 in The Straits Times.
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