Ong Pang Siew v Public Prosecutor: Murder Conviction Appeal Based on Diminished Responsibility

Ong Pang Siew appealed to the Court of Appeal of Singapore against his conviction for the murder of his step-daughter. The High Court had rejected his defense of diminished responsibility. The Court of Appeal, comprising Chan Sek Keong CJ, Andrew Phang Boon Leong JA, and V K Rajah JA, allowed the appeal, finding that Ong Pang Siew was suffering from a major depressive disorder that substantially impaired his mental responsibility at the time of the offense. The court set aside the murder conviction and convicted him of culpable homicide not amounting to murder.

1. Case Overview

1.1 Court

Court of Appeal

1.2 Outcome

Conviction on the charge of murder set aside; convicted on a charge of culpable homicide not amounting to murder.

1.3 Case Type

Criminal

1.4 Judgment Type

Written Judgment

1.5 Jurisdiction

Singapore

1.6 Description

Appeal against murder conviction. The Court of Appeal allowed the appeal, finding diminished responsibility due to major depressive disorder.

1.7 Decision Date

7 November 2010

2. Parties and Outcomes

Party Name	Role	Type	Outcome	Outcome Type	Counsels
Public Prosecutor	Respondent	Government Agency	Appeal Lost	Lost	Bala Reddy of Attorney-General’s Chamber Prem Raj of Attorney-General’s Chamber
Ong Pang Siew	Appellant	Individual	Appeal Allowed	Won	Sunil Sudheesan of KhattarWong Subhas Anandan of KhattarWong

3. Judges

Judge Name	Title	Delivered Judgment
Chan Sek Keong	Chief Justice	No
Andrew Phang Boon Leong	Justice of the Court of Appeal	No
V K Rajah	Justice of the Court of Appeal	Yes

4. Counsels

Counsel Name	Organization
Bala Reddy	Attorney-General’s Chamber
Prem Raj	Attorney-General’s Chamber
Sunil Sudheesan	KhattarWong
Subhas Anandan	KhattarWong

4. Facts

The appellant was charged with murder under s 302 of the Penal Code for causing the death of his step-daughter.
The appellant had been married to the deceased's mother, Xiu Yanhong, but they were undergoing divorce proceedings.
On the day of the incident, the appellant had been drinking beer with friends before going to Xiu's flat.
At Xiu's flat, the appellant strangled the deceased, causing her death.
The appellant had a blood alcohol content of 84 mg of ethanol per 100ml of blood three hours after the offence.
The appellant had a history of marital problems, financial difficulties, and a family history of mental disorder.
The appellant was observed to be behaving abnormally after the killing, including laughing, crying, and banging his head against the wall.

5. Formal Citations

Ong Pang Siew v Public Prosecutor, Criminal Appeal No 4 of 2009, [2010] SGCA 37
Public Prosecutor v Ong Pang Siew, , [2009] 4 SLR(R) 474

6. Timeline

Date	Event
1997-01-01	Appellant met Xiu Yanhong.
1998-01-01	Factory where Xiu Yanhong worked closed down.
1999-11-01	Xiu Yanhong's work permit expired; she returned to China.
2001-01-01	Xiu Yanhong divorced the deceased’s biological father.
2002-01-01	Xiu Yanhong returned to Singapore and married the appellant.
2002-11-01	The deceased arrived in Singapore.
2003-08-08	Xiu Yanhong gave birth to GHK.
2005-01-01	Xiu Yanhong had two miscarriages.
2006-01-01	Xiu Yanhong started her own massage parlour.
2007-03-01	Appellant and Xiu Yanhong had a heated argument.
2007-04-01	Xiu Yanhong moved out of the matrimonial home.
2007-05-15	Xiu Yanhong initiated divorce proceedings.
2007-08-01	Xiu Yanhong secured her Singapore citizenship.
2007-10-01	Xiu Yanhong obtained sole custody of the deceased.
2007-10-20	Ong Pang Siew killed Ong Pan Hui.
2007-10-21	Autopsy was carried out on the deceased.
2008-08-01	Dr. Tommy Tan examined the appellant.
2010-11-08	Judgment reserved.

7. Legal Issues

Diminished Responsibility
- Outcome: The court found that the appellant was suffering from such abnormality of mind as substantially impaired his mental responsibility for his acts and omissions in causing the death.
- Category: Substantive
- Sub-Issues:
  - Abnormality of mind
  - Substantial impairment of mental responsibility
  - Major depressive disorder
Intention to Kill
- Outcome: The court found that the appellant did not go to the flat with the intention of killing the deceased, but formed the intention after he had 'snapped'.
- Category: Substantive
Intention to Cause Injury Sufficient to Cause Death
- Outcome: The court found that the appellant intended to cause injuries to the deceased's neck which were sufficient in the ordinary course of nature to cause death.
- Category: Substantive
Assessment of Expert Evidence
- Outcome: The court assessed the conflicting expert evidence, preferring the opinion that the appellant suffered from a major depressive disorder.
- Category: Procedural

8. Remedies Sought

Appeal against Murder Conviction
Defence of Diminished Responsibility

9. Cause of Actions

Murder
Culpable Homicide Not Amounting to Murder

10. Practice Areas

Criminal Appeals
Homicide Defense

11. Industries

No industries specified

12. Cited Cases

Case Name	Court	Affirmed	Citation	Jurisdiction	Significance
Public Prosecutor v Ong Pang Siew	High Court	Yes	[2009] 4 SLR(R) 474	Singapore	The High Court's decision that the appellant intended to cause the deceased’s death when he went to Xiu’s flat is referenced.
Sakthivel Punithavathi v Public Prosecutor	Court of Appeal	Yes	[2007] 2 SLR(R) 983	Singapore	Cited for the principles to be applied by an appellate court in assessing a trial judge’s findings on expert evidence.
Saeng-Un Udom v PP	High Court	Yes	[2001] 2 SLR(R) 1	Singapore	Cited for the principle that a judge is not entitled to substitute his own views for those of an uncontradicted expert's.
Antonio Caldeira Dias v Frederick Augustus Gray	N/A	Yes	AIR 1936 Journal 154	N/A	Cited for the principle that an appellate court will be slow to criticise without good reason a trial court's findings on expert evidence.
Chua Hwa Soon Jimmy v Public Prosecutor	Court of Appeal	Yes	[1998] 1 SLR(R) 601	Singapore	Cited for the principle that the appellant bears the burden of proving the defence of diminished responsibility on a balance of probabilities.
Took Leng How v Public Prosecutor	Court of Appeal	Yes	[2006] 2 SLR(R) 70	Singapore	Cited for the three-limb test which an accused has to satisfy to establish the defence of diminished responsibility.
Walton v The Queen	Privy Council	Yes	[1978] 1 AC 788	N/A	Cited for the principle that the trial judge is entitled and indeed bound to consider not only the medical evidence but the evidence upon the whole facts and circumstances of the case.
R v Byrne	Court of Criminal Appeal	Yes	[1960] 2 QB 396	England and Wales	Cited for the definition of 'abnormality of mind' under the defence of diminished responsibility.
Elvan Rose v The Queen	Privy Council	Yes	[1961] AC 496	N/A	Cited for accepting the interpretation of the words “abnormality of mind” and “mental responsibility” as authoritative and correct.
Mansoor s/o Abdullah and another v Public Prosecutor	Court of Appeal	Yes	[1998] 3 SLR(R) 403	Singapore	Cited for accepting the interpretation in R v Byrne of the term ‘abnormality of mind’.
R v Seers	Court of Appeal	Yes	(1984) 79 Cr App R 261	England and Wales	Cited for the holding that chronic reactive depression could on the evidence before him sustain the defence of diminished responsibility.
R v Bathurst	Court of Appeal	Yes	[1968] 2 QB 99	England and Wales	Cited for the principle that a reactive depression caused by extreme adversity or stress may establish the exception.
G Krishnasamy Naidu v Public Prosecutor	High Court	Yes	[2006] 4 SLR(R) 874	Singapore	Cited for the principle that a reactive depression caused by extreme adversity or stress may establish the exception.
Public Prosecutor v Juminem and another	High Court	Yes	[2005] 4 SLR(R) 536	Singapore	Cited for the principle that a reactive depression caused by extreme adversity or stress may establish the exception.
Regina v Lloyd	Court of Appeal	Yes	[1967] 1 QB 175	England and Wales	Cited for the principle that substantial does not require a total impairment; neither is it trivial nor minimal.
Zailani bin Ahmad v Public Prosecutor	Court of Appeal	Yes	[2005] 1 SLR(R) 356	Singapore	Cited for the principle that whether an accused’s mental responsibility was substantially impaired is ultimately a question to be decided by the court based on all the evidence before it.
Jagatheesan s/o Krishnasamy v Public Prosecutor	Court of Appeal	Yes	[2006] 4 SLR(R) 45	Singapore	Cited for the principle that an appellate court is as competent as any trial judge to draw any necessary inferences of fact from the circumstances of the case.
Browne v Dunn	N/A	Yes	(1893) 6 R 67	N/A	Cited for the rule of evidence that if what a witness says is not challenged, the evidence is deemed to have been admitted.
Yeo Kwan Wee Kenneth v Public Prosecutor	High Court	Yes	[2004] 2 SLR(R) 45	Singapore	Cited for the purpose of the rule in Browne v Dunn is to secure procedural fairness in litigation.
Tengku Jonaris Badlishah v Public Prosecutor	Court of Appeal	Yes	[1999] 1 SLR(R) 800	Singapore	Cited for the principle that self-induced intoxication is not a specified cause under limb (b) of the defence of diminished responsibility.

13. Applicable Rules

Rule Name
No applicable rules

14. Applicable Statutes

Statute Name	Jurisdiction
Penal Code	Singapore
s 302 of the Penal Code	Singapore
s 300 of the Penal Code	Singapore
s 304(a) of the Penal Code	Singapore

15. Key Terms and Keywords

15.1 Key Terms

Diminished Responsibility
Major Depressive Disorder
Abnormality of Mind
Mental Responsibility
Culpable Homicide
Expert Evidence
Strangulation
Intention to Kill
Alcohol Intoxication

15.2 Keywords

Murder
Diminished Responsibility
Mental Disorder
Appeal
Singapore
Criminal Law
Culpable Homicide

17. Areas of Law

Area Name	Relevance Score
Criminal Law	95
Murder	90
Homicide	70
Criminal Procedure	60
Evidence Law	50

16. Subjects

Criminal Law
Mental Health Law
Criminal Procedure