Case Details
- Citation: [2025] SGCA 8
- Title: Azuin bin Mohd Tap v Public Prosecutor
- Court: Court of Appeal of the Republic of Singapore
- Court Type: Criminal appeal / criminal motion
- Case Number: Court of Appeal / Criminal Motion No 48 of 2024
- Date of Decision: 27 February 2025
- Judges: Sundaresh Menon CJ, Tay Yong Kwang JCA and Steven Chong JCA
- Applicant: Azuin bin Mohd Tap
- Respondent: Public Prosecutor
- Procedural Posture: Application for leave to adduce further evidence on appeal (fresh expert evidence)
- Lower Court Reference: Public Prosecutor v Hashim bin Ismail and others [2023] SGHC 165 (GD)
- Legal Areas: Criminal Procedure and Sentencing — Appeal; Criminal Procedure and Sentencing — Appeal (adducing fresh evidence)
- Statutes Referenced: Misuse of Drugs Act (Cap 185, 2008 Rev Ed) (“MDA”)
- Key Statutory Provisions: s 33B(1) and s 33B(3) of the MDA
- Cases Cited (as provided): [2021] SGCA 18; [2023] SGHC 165; [2025] SGCA 8
- Additional Cases Cited in Extract (as provided in text): Miya Manik v Public Prosecutor and another matter [2021] 2 SLR 1169; Ladd v Marshall [1954] 1 WLR 1489; Soh Meiyun v Public Prosecutor [2014] 3 SLR 299; Dzulkarnain bin Khamis v Public Prosecutor and another appeal and another matter [2023] 1 SLR 1398; AnAn Group (Singapore) Pte Ltd v VTB Bank (Public Joint Stock Co) [2019] 2 SLR 341; Public Prosecutor v Mohd Ariffan bin Mohd Hassan [2018] 1 SLR 544; Nagaenthran a/l K Dharmalingam v Public Prosecutor and another appeal [2019] 2 SLR 216
- Judgment Length: 18 pages, 5,155 words
- Decision Type: Ex tempore judgment
Summary
In Azuin bin Mohd Tap v Public Prosecutor ([2025] SGCA 8), the Court of Appeal dismissed the applicant’s criminal motion seeking leave to adduce two new psychiatric/neuropsychological reports on appeal. The applicant had been convicted on a capital charge of drug trafficking and sentenced to the mandatory death penalty. At trial, he did not dispute the charge; instead, he sought to bring himself within the alternative sentencing regime under s 33B(1) of the Misuse of Drugs Act (“MDA”) by proving “diminished responsibility”.
The Court of Appeal held that the proposed fresh expert evidence was not material to the appeal because it did not overcome a critical deficiency: the new psychiatric report accepted that at least one of the statutory limbs for diminished responsibility was not made out. In addition to this primary ground, the Court expressed broader concern that the applicant’s approach amounted to “expert shopping” after an adverse decision below—an abuse of process that the court had previously cautioned against, even in criminal proceedings where the stakes are high.
What Were the Facts of This Case?
The applicant, Azuin bin Mohd Tap, was convicted by a High Court judge on a capital charge of drug trafficking and sentenced to the mandatory death penalty. The conviction arose in proceedings where the applicant did not contest the fact of trafficking. Instead, his defence strategy focused on sentencing relief under the MDA. In particular, he attempted to satisfy the requirements for diminished responsibility so as to qualify for an alternative sentencing regime rather than the mandatory death penalty.
Under the MDA framework, diminished responsibility is not a general mitigation concept; it is a statutory defence with specific elements. The Court of Appeal noted that, to establish diminished responsibility, the applicant had to show: (a) an abnormality of mind; (b) that abnormality of mind was caused by one of three specified aetiologies (arrested or retarded development of mind, inherent cause, or disease or injury); and (c) the abnormality of mind substantially impaired his mental responsibility for his acts and omissions in relation to the offence. The Court of Appeal referred to the High Court’s articulation of these requirements, citing the established approach in Nagaenthran a/l K Dharmalingam v Public Prosecutor and the High Court’s own reasoning in the GD.
At trial, the applicant’s involvement was limited to that of a courier. However, he was not issued a certificate of substantive assistance by the Public Prosecutor. As a result, the sentencing contest narrowed: the sole live issue before the judge was whether the applicant suffered from diminished responsibility under s 33B(1)(b) read with s 33B(3) of the MDA.
The factual and evidential battleground at trial was expert psychiatric evidence. The prosecution relied on Dr Kenneth Koh, while the applicant relied on Dr Julia Lam. Both experts agreed that the applicant suffered from opioid use disorder and stimulant use disorder. Their disagreement concerned whether the applicant also suffered from persistent depressive disorder. The applicant’s theory was that the combination of persistent depressive disorder, opioid use disorder, and stimulant use disorder caused a substantial impairment of his mental responsibility. The judge, however, found that the applicant did not suffer from persistent depressive disorder at the material time, preferring Dr Koh’s evidence over Dr Lam’s.
What Were the Key Legal Issues?
The immediate legal issue before the Court of Appeal was whether the applicant should be granted leave to adduce further evidence on appeal. This required the court to consider the well-known conditions for admitting fresh evidence on appeal, derived from Ladd v Marshall: non-availability with reasonable diligence at trial, materiality (probable influence on the result), and reliability (credibility).
Although the Ladd v Marshall framework is applied with some attenuation in criminal matters where an accused person seeks to adduce further evidence, the Court of Appeal emphasised that the non-availability condition is not entirely dispensed with; instead, it must be assessed holistically in light of materiality and reliability. The Court therefore had to decide whether the proposed new reports met the threshold for admission.
A second, broader issue—though not framed as a formal element of the Ladd v Marshall test—concerned the integrity of the appellate process. The Court asked whether the applicant’s conduct in obtaining and deploying successive expert reports after an adverse trial outcome amounted to an abuse of process, particularly where the new evidence appeared to be aimed at generating alternative arguments rather than addressing a genuine evidential gap.
How Did the Court Analyse the Issues?
The Court of Appeal began by restating the governing principles for admitting fresh evidence on appeal. It confirmed that the admission of further evidence is traditionally governed by the three Ladd v Marshall conditions: (1) the evidence must not have been available at trial despite reasonable diligence; (2) it must be material in the sense that it would probably have an important influence on the result; and (3) it must be reliable, meaning apparently credible. The Court also cited the approach in Soh Meiyun and Dzulkarnain for these requirements.
However, the Court then addressed the special context of criminal motions by an accused person. It referred to AnAn Group and Public Prosecutor v Mohd Ariffan bin Mohd Hassan for the proposition that, in criminal matters, the first Ladd v Marshall condition (non-availability) is “less paramount” than the other two conditions. The Court clarified in Miya Manik that this does not mean non-availability is irrelevant; rather, the court should evaluate non-availability holistically alongside materiality and reliability.
Applying these principles, the Court of Appeal identified the “insurmountable difficulty” in the applicant’s motion: the new expert evidence was immaterial to the appeal. The applicant sought to adduce two new reports: (i) a psychiatric report by Dr Jacob Rajesh, and (ii) a neuropsychological assessment report by Ms Low Yung Ling. While the reports were interlinked—Dr Rajesh had referred the applicant to Ms Low to assess intellectual functioning—the Court focused on whether the evidence could realistically affect the legal outcome on diminished responsibility.
Dr Rajesh’s report opined that the applicant suffered from an abnormality of mind in the form of moderate opioid use disorder and that this substantially impaired his mental responsibility because it caused a preoccupation with procuring drugs, leading him to resort to drug trafficking to feed his addiction. Yet, critically, Dr Rajesh acknowledged that the applicant’s opioid use disorder did not arise from one of the three recognised aetiologies under s 33B(3)(b) of the MDA. This concession was decisive. Because diminished responsibility under s 33B requires that the abnormality of mind be caused by one of the statutory aetiologies, the new report did not bridge the missing statutory element.
In other words, even if the psychiatric report supported impairment, it did not satisfy the causation/aetiology limb. The Court therefore reasoned that the evidence could not have an influence on the result of the appeal because it accepted that at least one of the statutory limbs was not made out. The Court’s analysis treated this as fatal to materiality: evidence that does not address the legal deficiency in the applicant’s diminished responsibility case cannot be “material” for the purpose of admitting fresh evidence.
Ms Low’s neuropsychological assessment, which suggested that the applicant did not meet criteria for any intellectual disability or disorder, similarly did not assist the applicant in satisfying the statutory requirements. The Court’s reasoning indicates that the new evidence did not provide a pathway to establish the required abnormality of mind caused by one of the specified aetiologies, nor did it undermine the trial judge’s core findings in a way that could affect the appeal’s outcome.
Beyond immateriality, the Court addressed a more general concern: the applicant’s attempt at “expert shopping”. The Court observed that the applicant’s motion appeared to be designed to lay groundwork for running new and even inconsistent lines of argument on appeal from the case he had advanced before the trial judge. The Court noted that it had previously cautioned against abuse of process in this context, citing Miya Manik. It took the opportunity to make clear that expert shopping of the kind mounted in this case falls squarely within conduct amounting to an abuse of process.
Although the Court’s primary reason for dismissal was immateriality, its discussion of expert shopping signals an important procedural message: appellate courts will not tolerate strategic procurement of expert opinions after an adverse outcome where the evidence is not genuinely directed at correcting a material evidential gap. The Court’s approach reflects a balancing of fairness to the accused with the need to prevent manipulation of the appellate process and the efficient administration of justice.
What Was the Outcome?
The Court of Appeal dismissed the applicant’s application for leave to adduce further evidence. The dismissal was grounded primarily on the immateriality of the proposed expert reports to the appeal, because the new psychiatric evidence conceded that a key statutory limb for diminished responsibility was not satisfied.
In addition, the Court expressly cautioned against “expert shopping” and treated the applicant’s conduct as raising an abuse of process concern. Practically, the applicant’s appeal proceeded without the benefit of the fresh reports, leaving the trial judge’s findings and reasoning intact for the purposes of the appeal.
Why Does This Case Matter?
This decision is significant for practitioners because it clarifies how the Court of Appeal will apply the fresh evidence framework in criminal appeals, particularly where the proposed evidence is expert evidence. While the court recognises that criminal motions may apply the Ladd v Marshall test with some attenuation regarding non-availability, the decision underscores that materiality remains a stringent gatekeeping requirement. Evidence that does not address the statutory elements of diminished responsibility—especially the aetiology limb under s 33B(3)—will not be admitted, even if it is presented by a new expert.
Second, the judgment provides a clear warning about expert shopping. The Court’s language indicates that the appellate process cannot be treated as a forum for iterative re-labelling of psychiatric narratives after an adverse trial outcome. Where successive experts are engaged in a manner that produces inconsistent theories or attempts to reframe the case without addressing the legal deficiencies identified below, the court may view the conduct as an abuse of process.
For defence counsel, the case highlights the importance of aligning expert evidence with the statutory structure of the defence. In diminished responsibility cases under the MDA, it is not enough to show impairment; the evidence must also satisfy the causation/aetiology requirements. For prosecutors, the decision supports arguments that fresh expert evidence should be scrutinised not only for credibility but also for its legal relevance to the elements that were missing at trial.
Legislation Referenced
- Misuse of Drugs Act (Cap 185, 2008 Rev Ed), s 33B(1) and s 33B(3)
Cases Cited
- Azuin bin Mohd Tap v Public Prosecutor [2025] SGCA 8
- Public Prosecutor v Hashim bin Ismail and others [2023] SGHC 165
- Miya Manik v Public Prosecutor and another matter [2021] 2 SLR 1169
- Ladd v Marshall [1954] 1 WLR 1489
- Soh Meiyun v Public Prosecutor [2014] 3 SLR 299
- Dzulkarnain bin Khamis v Public Prosecutor and another appeal and another matter [2023] 1 SLR 1398
- AnAn Group (Singapore) Pte Ltd v VTB Bank (Public Joint Stock Co) [2019] 2 SLR 341
- Public Prosecutor v Mohd Ariffan bin Mohd Hassan [2018] 1 SLR 544
- Nagaenthran a/l K Dharmalingam v Public Prosecutor and another appeal [2019] 2 SLR 216
Source Documents
This article analyses [2025] SGCA 8 for legal research and educational purposes. It does not constitute legal advice. Readers should consult the full judgment for the Court's complete reasoning.