Teo Ghim Heng v Public Prosecutor: Murder, Diminished Responsibility & Constitutional Challenges

Teo Ghim Heng appealed to the Court of Appeal of Singapore against his conviction in the High Court for the murder of his wife, Choong Pei Shan, and daughter, Teo Zi Ning. The Court of Appeal, comprising Sundaresh Menon CJ, Judith Prakash JCA, Steven Chong JCA, Belinda Ang Saw Ean JAD, and Chao Hick Tin SJ, heard the appeal on 13 October 2021, and reserved judgment until 23 February 2022. Teo Ghim Heng challenged the constitutionality of sections 299 and 300(a) of the Penal Code. The Court of Appeal dismissed the appeal, upholding the conviction and sentence.

1. Case Overview

1.1 Court

Court of Appeal of the Republic of Singapore

1.2 Outcome

Appeal Dismissed

1.3 Case Type

Criminal

1.4 Judgment Type

Judgment

1.5 Jurisdiction

Singapore

1.6 Description

Singapore Court of Appeal dismisses Teo Ghim Heng's appeal against his murder conviction, rejecting diminished responsibility and constitutional challenges.

1.7 Decision Date

22 February 2022

2. Parties and Outcomes

Party Name	Role	Type	Outcome	Outcome Type	Counsels
Public Prosecutor	Respondent	Government Agency	Appeal Dismissed	Won	Ng Jun Chong of Attorney-General’s Chambers Winston Man of Attorney-General’s Chambers Dillon Kok of Attorney-General’s Chambers
Teo Ghim Heng	Appellant	Individual	Appeal Dismissed	Lost	Suang Wijaya of Eugene Thuraisingam LLP Eugene Singarajah Thuraisingam of Eugene Thuraisingam LLP Johannes Hadi of Eugene Thuraisingam LLP Ng Clare Sophia of Eugene Thuraisingam LLP Koh Wen Rui Genghis of Eugene Thuraisingam LLP

3. Judges

Judge Name	Title	Delivered Judgment
Judith Prakash	Justice of the Court of Appeal	Yes
Sundaresh Menon	Chief Justice	No
Steven Chong	Justice of the Court of Appeal	No
Belinda Ang Saw Ean	Judge of the Appellate Division	No
Chao Hick Tin	Senior Judge	No

4. Counsels

Counsel Name	Organization
Ng Jun Chong	Attorney-General’s Chambers
Winston Man	Attorney-General’s Chambers
Dillon Kok	Attorney-General’s Chambers
Suang Wijaya	Eugene Thuraisingam LLP
Eugene Singarajah Thuraisingam	Eugene Thuraisingam LLP
Johannes Hadi	Eugene Thuraisingam LLP
Ng Clare Sophia	Eugene Thuraisingam LLP
Koh Wen Rui Genghis	Eugene Thuraisingam LLP

4. Facts

Appellant was charged with murder of his wife and daughter under s 300(a) of the Penal Code.
Appellant admitted to killing his wife and daughter but raised the defenses of diminished responsibility and grave and sudden provocation.
Appellant claimed to be suffering from moderate Major Depressive Disorder (MDD) at the time of the offences.
Appellant challenged the constitutionality of ss 299 and 300(a) of the Penal Code.
The High Court rejected the appellant's defenses and constitutional challenges.
The appellant appealed against the High Court's decision.

5. Formal Citations

Teo Ghim Heng v Public Prosecutor, Criminal Appeal No 36 of 2020, [2022] SGCA 10
Public Prosecutor v Teo Ghim Heng (Zhang Jinxing), , [2021] SGHC 13

6. Timeline

Date	Event
2015-01-01	Downturn in the property market caused the appellant’s income to decline significantly.
2016-10-01	Appellant joined Carpentry Design Works Pte Ltd as a sales coordinator.
2017-01-19	Playschool principal requested payment of Zi Ning’s overdue school fees.
2017-01-20	Appellant killed Pei Shan and Zi Ning.
2017-01-20	Appellant attempted suicide by slitting his wrists.
2017-01-20	Appellant attempted suicide by overdosing on Panadol.
2017-01-21	Appellant attempted suicide by consuming rat poison but was unable to purchase it.
2017-01-22	Appellant resolved to commit suicide by jumping to his death but failed to go through with this plan.
2017-01-23	CDW colleagues visited his house to look for him.
2017-01-24	Appellant contemplated committing suicide by jumping, but put it off again.
2017-01-25	Appellant attempted suicide by consuming 105 Panadol tablets.
2017-01-26	Appellant attempted to slit his left wrist again using a penknife blade.
2017-01-26	Appellant sprayed a large quantity of insecticide into his water and drank the mixture.
2017-01-28	Appellant resolved to burn Pei Shan’s and Zi Ning’s bodies, immolating himself in the process but chickened out.
2017-01-28	Appellant formulated a plan to drown himself in the sea at Sembawang Park, but again failed to see this plan through to completion.
2017-01-28	Pei Shan’s and Zi Ning’s deaths were discovered.
2017-01-28	Appellant was arrested.
2017-01-31	Dr Ong provisionally diagnosed the appellant as having “depression with homicidal act and persistent suicidal intent”.
2017-04-21	Dr Yeo prepared his First Report.
2018-10-19	Dr Rajesh prepared his First Report.
2019-03-15	Dr Yeo prepared his Second Report.
2019-05-07	Dr Rajesh prepared his Second Report.
2021-10-13	Appeal heard by the Court of Appeal.
2022-02-23	Judgment reserved by the Court of Appeal.

7. Legal Issues

Diminished Responsibility
- Outcome: The court held that the defense of diminished responsibility was not made out as the appellant was not suffering from Major Depressive Disorder at the time of the offences.
- Category: Substantive
- Sub-Issues:
  - Abnormality of mind
  - Substantial impairment of mental responsibility
  - Major Depressive Disorder
Constitutionality of Penal Code Sections 299 and 300(a)
- Outcome: The court held that sections 299 and 300(a) of the Penal Code are constitutional and do not offend the separation of powers doctrine or contravene Article 12 of the Constitution.
- Category: Constitutional
- Sub-Issues:
  - Separation of powers
  - Equality before the law
  - Prosecutorial discretion

8. Remedies Sought

Appeal against conviction and sentence

9. Cause of Actions

Murder

10. Practice Areas

Criminal Appeals
Constitutional Law
Homicide Law

11. Industries

No industries specified

12. Cited Cases

Case Name	Court	Affirmed	Citation	Jurisdiction	Significance
Public Prosecutor v Teo Ghim Heng (Zhang Jinxing)	High Court	Yes	[2021] SGHC 13	Singapore	Sets out the facts of the case and the High Court Judge's decision.
Nagaenthran a/l K Dharmalingam v Public Prosecutor and another appeal	Court of Appeal	Yes	[2019] 2 SLR 216	Singapore	Cited for the principle that the appellant must prove the defence of diminished responsibility on a balance of probabilities.
Ong Pang Siew v Public Prosecutor	Court of Appeal	Yes	[2011] 1 SLR 606	Singapore	Cited for the principle that the appellant must prove the defence of diminished responsibility on a balance of probabilities.
Sakthivel Punithavathi v Public Prosecutor	Court of Appeal	Yes	[2007] 2 SLR(R) 983	Singapore	Cited for the principle that an appellate court will be slow to criticise a trial court’s findings on expert evidence without good reason.
Kanagaratnam Nicholas Jens v Public Prosecutor	Court of Appeal	Yes	[2019] 5 SLR 887	Singapore	Cited for the principle that in assessing and weighing expert medical evidence in general, it is necessary for the court to examine the underlying evidence and the analytical process by which the experts’ conclusions are reached.
Ilechukwu Uchechukwu Chukwudi v Public Prosecutor	Court of Appeal	Yes	[2021] 1 SLR 67	Singapore	Cited for the principle that the court must consider “the cogency and the limits of the medical evidence complemented by, where appropriate, an understanding of human experience and common sense”.
Saeng-Un Udom v Public Prosecutor	Court of Appeal	Yes	[2001] 2 SLR(R) 1	Singapore	Cited for the principle that the court is not obliged to accept expert evidence by reason only that it is unchallenged.
Public Prosecutor v P Mageswaran and another appeal	Court of Appeal	Yes	[2019] 1 SLR 1253	Singapore	Cited to define the types of intention which will make an act of killing, an act of culpable homicide. Overruled on the point that the ingredients of the crime under the first limb of s 299 are exactly the same as the ingredients of the crime under s 300(a).
Saravanan Chandaram v Public Prosecutor and another matter	Court of Appeal	Yes	[2020] 2 SLR 95	Singapore	Cited for the principle that the presumption of constitutionality in the context of the validity of legislation is no more than a starting point.
Prabagaran a/l Srivijayan v Public Prosecutor and other matters	Court of Appeal	Yes	[2017] 1 SLR 173	Singapore	Cited for the principle that the legislature has the power to prescribe punishment, whilst judicial power lies in exercising such sentencing discretion as conferred by statute to select the appropriate punishment.
Hinds v The Queen	Privy Council	Yes	[1977] AC 195	United Kingdom	Cited for the principle that it is not within Parliament’s remit to transfer from the judiciary to an executive body the discretion to determine the appropriate punishment for a particular offender.
Deaton v Attorney-General and the Revenue Commissioners	Supreme Court	Yes	[1963] IR 170	Ireland	Cited as an example of legislation which enables the Executive to select the sentence to be imposed in a particular case after the accused person has been convicted.
Palling v Corfield	High Court	Yes	(1970) 123 CLR 52	Australia	Cited as an example of legislation which enables the Executive to select the sentence to be imposed in a particular case after the accused person has been convicted.
Mohammed Muktar Ali v The Queen	Privy Council	Yes	[1992] 2 AC 93	United Kingdom	Cited as an example of legislation which enables the Executive to make administrative decisions which are directly related to the charges brought against a particular accused person at the time of those decisions, and which have an impact on the actual sentence eventually imposed by a court of law. Distinguished from the present case.
State of South Australia v Totani	High Court	Yes	(2010) 242 CLR 1	Australia	Cited as an example of legislation which enables the Executive to make administrative decisions which are not directly related to any charges brought against a particular accused person, but which have an impact on the actual sentence eventually imposed by a court of law.
Mohammad Faizal bin Sabtu v Public Prosecutor	Court of Appeal	Yes	[2012] 4 SLR 947	Singapore	Cited for the principle that a statute providing for a mandatory sentence does not infringe upon judicial power.
Lim Meng Suang and another v Attorney-General and another appeal and another matter	Court of Appeal	Yes	[2015] 1 SLR 26	Singapore	Cited for the established test for the constitutionality of legislation under Art 12(1) of the Constitution, which is the “reasonable classification” test.
Taw Cheng Kong v Public Prosecutor	Court of Appeal	Yes	[1998] 2 SLR(R) 489	Singapore	Cited for the established test for the constitutionality of legislation under Art 12(1) of the Constitution, which is the “reasonable classification” test.
Syed Suhail bin Syed Zin v Attorney-General	Court of Appeal	Yes	[2021] 1 SLR 809	Singapore	Cited for the test for the constitutionality of legislation under Art 12(1) of the Constitution.

13. Applicable Rules

Rule Name
No applicable rules

14. Applicable Statutes

Statute Name	Jurisdiction
Penal Code (Cap 224, 2008 Rev Ed) s 300(a)	Singapore
Penal Code (Cap 224, 2008 Rev Ed) s 299	Singapore
Penal Code (Cap 224, 2008 Rev Ed) Exception 7 to s 300	Singapore
Constitution of the Republic of Singapore Art 12(1)	Singapore

15. Key Terms and Keywords

15.1 Key Terms

Murder
Diminished responsibility
Major Depressive Disorder
Constitutionality
Separation of powers
Equality before the law
Prosecutorial discretion
Penal Code
Constitution
Expert evidence

15.2 Keywords

Murder
Diminished Responsibility
Constitutional Law
Singapore
Criminal Appeal

17. Areas of Law

Area Name	Relevance Score
Murder	95
Criminal Law	90
Offences	90
Constitutional Law	85

16. Subjects

Criminal Law
Constitutional Law