The Singapore Law Gazette

The Role of Prosecutors as Ministers of Justice

Disclosure of Unused Material, and Calling of Witnesses at Trial (Part II)

This two-part article examines two aspects intimately related to a prosecutor’s role as a Minister of Justice – the Prosecution’s duty to disclose unused material, and its discretion to call witnesses at trial. The first part (published in last month’s issue) considered issues in relation to Prosecution’s duty to disclose unused material. This part offers: a) a brief examination of recent case law developments vis-à-vis the Prosecution’s discretion to call witnesses at trial, and b) a discussion on some challenging questions that these particular developments potentially raise.

Calling of Witnesses at Trial

This portion of this article focusses on prosecutors’ discretion to call witnesses at trial. It begins with a brief examination of recent case law developments on this issue, which has become inextricably linked with the issue of the Prosecution and Defence’s evidential burden during a trial. This is followed by a discussion on some challenging questions that these particular developments potentially raise.

Recent Developments in the Law

The Court of Appeal in Muhammad Nabill bin Mohd Faud v PP (Nabill)¹(2020) 1 SLR 984. (other than on the issue of Prosecution’s duty to disclose unused material, discussed in the previous part of this article) also dealt at some length with the issue of whether the Prosecution has a duty to call a material witness, that is, a witness who can be expected to confirm or contradict the Defence in material respects, at a trial. In that regard, it made two key holdings.

The first holding is that there is no such legal duty on the part of the Prosecution. It affirmed the position taken in a previous case that it is instead the Prosecution’s discretion whether or not to call a particular witness, provided it does not have an ulterior motive (and presumably also had not acted in bad faith) underlying its decision, and the witness, who is available to, but not called by, the Prosecution, is offered to the Defence.²Nabill, supra n 1 at (57)-(66). The Court noted that this is also the position taken in other jurisdictions such as Malaysia and England and Wales. Australia takes a different position, but the court in Nabill noted that this is to some extent due to the fact that the Australian Evidence Act 1995³Act No 2 of 1995 (Cth). allows the Prosecution to cross-examine its own witness if that witness’ evidence is unfavourable.

The second holding is that although the Prosecution does not have a legal duty to call material witnesses, there are two potential consequences of its decision to not call a particular material witness:⁴Nabill, supra n 1 at (67)-(82).

1. Where the Prosecution has an evidential burden to rebut a defence advanced by an accused, the non-calling of a material witness may, in appropriate circumstances, result in the Prosecution failing to discharge that evidential burden.
2. In certain circumstances, where the Prosecution does not call a material witness, the Court may be entitled to draw an adverse inference pursuant to section 116, Illustration (g) of the Evidence Act⁵Cap 97, 1997 Rev Ed. that the evidence of a material witness would have been unfavourable to the Prosecution.

No Legal Duty on Part of Prosecution to Call Material Witnesses

This author agrees with the court in Nabill that unlike the issue on disclosure of unused material, the Prosecution should not be held to have a legal duty to call individual material witnesses. Apart from the fact that a similar position has been taken elsewhere, there are additional persuasive reasons for why the Prosecution should not have such a duty. Firstly, and perhaps most importantly, the Constitution of the Republic of Singapore not only regards the prosecutorial power as equal in status to the judicial power,⁶Ramalingam Ravinthran v AG (2012) 2 SLR 49 at (43). its Article 35(8) grants the Attorney-General, qua Public Prosecutor, “the power, exercisable at his discretion, to institute, conduct or discontinue any proceedings for any offence”. The decision whether to disclose unused material is a more administrative one, and thus the Courts’ holding that the Prosecution has common law disclosure obligations would not be inconsistent with Article 35(8). However, the decision whether to call a witness at trial is a fundamental aspect of prosecutorial strategy,⁷See the Supreme Court of Canada case of R v Cook (1997) 1 SCR 1113 at (19) (“Cook”). so holding that the Prosecution has a common law duty to call certain witnesses would arguably be an undermining of its constitutional power to “conduct” criminal proceedings.

Secondly, an important motivation behind developing certain rules concerning prosecutors as Ministers of Justice is the recognition that there is need to promote equality of arms between the Prosecution and Defence in every case.⁸David Plater, “The Changing Role of the Modern Prosecutor: Has the Notion of the ‘Minister of Justice’ Outlived its Usefulness” (April 2011), <https://eprints.utas.edu.au/10743/2/David_Plater_whole.pdf> (“Changing Role of the Modern Prosecutor”) at (2.9.10). Where one party is more well-armed than the other, there are two principal ways to level the playing field. The first, and clearly better approach, is to boost the strength of the less well-armed side, without necessarily disarming the more well-armed side, to attain greater equality. This is what requiring more disclosure on the part of the Prosecution (to the Defence) seeks to do, and which is why it will be a relatively attractive solution to all stakeholders. Legally compelling the Prosecution to call certain witnesses against its considered wishes, is to engage the other approach, which is to substantively disarm the more well-armed side to try and achieve equality. Such an approach should generally not be taken except as a last resort. Furthermore, as has been observed, “… if the Prosecution chooses not to explore certain lines of inquiry with its witnesses or advance certain case theories, there might be good reasons for its choices, which the [court] might not fully appreciate.”⁹Nabill, supra n 1 at (67)-(82). It also swings the system a tad too far away from its adversarial core. The Court in Nabill highlighted that the Court’s fundamental objective in criminal trials is to arrive at a just outcome through a fair process.¹⁰Ibid at (47). And as has been underscored by other courts, the Prosecution too is entitled to a fair trial.¹¹See the various authorities cited in Changing Role of the Modern Prosecutor, supra n 8 at Ch 4, Part 7.

Indeed, if the suggestion in the previous part (of this article) to codify wider disclosure obligations on the part of the Prosecution is adopted, that would be a further reason in support of not legally requiring the Prosecution to call individual material witnesses, because wider disclosure would already bring about significantly greater equality between the two parties. That is in fact one important reason why the Supreme Court of Canada has declined to find that the Prosecution has a legal duty to call witnesses.¹²Cook, supra n 50 at (36).

That said, the Court in Nabill stated at a later part of its judgment that “… returning to first principles, the Prosecution is duty-bound to place before the court all relevant material to assist it in its determination of the truth”.¹³Nabill, supra n 1 at (77). The Court, in the even more recent case of Beh Chew Boo v PP (Beh Chew Boo)¹⁴(2020) SGCA 98. also commented that “[t]he Public Prosecutor is duty bound to serve the public interest by assisting the court to establish the truth. That would include putting forth relevant evidence, especially where [a material witness] was readily available …”¹⁵Ibid at (74). These statements, read in isolation, may seem to give the impression that the court is holding that the Prosecution does have a legal duty to call material witnesses. Nonetheless, for the reasons underscored above, these statements are probably better read as broad reminders that there is an overarching expectation on the part of the Prosecution to assist the Courts in the fact-finding process, and not that it has a specific legal duty to call material witnesses.

Evidential Burden

The general topic on evidential burden has been said to be a difficult and confusing one,¹⁶In Brady v Group Lotus Car Companies plc (1987) 2 All ER 674 at 687, Brown-Wilkinson VC went so far as to say that “(i)n my experience every time the phrase ‘evidential burden’ is used it leads to error”. and thus demands a full treatment in a separate article. However, it may be useful to highlight some brief observations here, not least because as pointed out, in Singapore the issue of the Prosecution’s decision to call witnesses has become inextricably linked with the issue of evidential burden, and also because the court’s position in Nabill and Beh Chew Boo on this issue is very challenging to rationalise. Both cases involved:

1. offenders facing capital offences under the Misuse of Drugs Act (MDA),¹⁷Cap 185, 2008 Rev Ed.
2. the Prosecution invoking presumptions under the Act against the respective offenders,
3. the Court finding that the offenders had discharged their evidential burden, and the evidential burden is hence shifted to the Prosecution,
4. the Court holding that because the Prosecution decided not to call certain material witnesses¹⁸The Prosecution had offered these witnesses to the Defence, but the Defence chose not to call them. to contradict the Defence, the Prosecution failed to discharge its evidential burden, and
5. the Court then concluding that the Defence has therefore rebutted the relevant presumptions.

To recap, the court in Nabill had held that where the Prosecution has an evidential burden to rebut a defence advanced by an accused, the non-calling of a material witness may, in appropriate circumstances, result in the Prosecution failing to discharge that evidential burden. That general holding is entirely unassailable. It is the Court’s specific stance on when the burden is discharged, and its relationship to the rebutting of an MDA presumption that raises two key difficulties.

The first difficulty is that the Court took the position that where a presumption under the MDA applies against the accused, the evidential burden on the accused is discharged as long as his case is not inherently incredible.¹⁹Nabill, supra n 1 at (71), (94(a)), (96), (103), (136) and (157), and Beh Chew Boo, supra n 14 at (66) and (80). It is not clear why the Court applied the threshold of inherent incredibility. It probably drew it from the threshold required for the Prosecution to show, at the end of the Prosecution’s case at a trial, that the Defence has a case to answer. That test, which was held by Lord Diplock in the Privy Council case of Haw Tua Tau v PP,²⁰(1981-1982) SLR(R) 133 at (16)-(17). is now enshrined in section 230(m) of the CPC. On a close reading, it may be noted that the test in fact consists of two sub-components – there is some evidence a) that is not inherently incredible, and additionally, b) that establishes or proves each and every element of the charge. If the evidence adduced by Prosecution is already inherently incredible, there is no need for the Court to waste further time to assess anything else, and the Defence simply need not be called. If the evidence is not inherently incredible, the Court then applies the more burdensome, but true, test, which is to assess whether there is some evidence to prove every element of the charge. As the eminent authors of Cross and Tapper on Evidence have opined, in this context “prove” must refer to proof beyond reasonable doubt.²¹Roderick Munday, Cross and Tapper on Evidence, 13^th ed (Oxford University Press, 2018) at 154. It is upon the fulfilment of this true test that the evidential burden is shifted to the counterparty.

Lord Diplock likely included the inherent incredibility component as a sort of back-of-the-envelope check against the Prosecution, because the Prosecution’s case may contain a mass of evidence to prove every element of the offence. If the quick check reveals that the Prosecution’s case is inherently incredible, the accused can simply be acquitted, and the court need not expend additional time and effort to assess whether the evidence would establish every element of the offence (which might even involve issues of law). This means that that inherent incredibility test is probably not suited nor necessary for transplant into the context of determining whether an accused has discharged its evidential burden vis-à-vis an MDA presumption.

Moreover, even if one wishes to apply the inherent incredibility test in that context, as has been pointed out by evidence scholars, the actual threshold at which the accused’s evidential burden is discharged in a situation where it has the legal burden to disprove a presumption is the same as that where it has the legal burden to prove a defence. That would be along the lines of whether there is evidence, if believed, capable of proving or sufficient to prove against the fact presumed, on the balance of probabilities.²²Ibid at 125 and 131. See also Dyson Heydon, Cross on Evidence, 12^th Australian ed (LexisNexis Butterworths, 2020) at (7045). Theoretically, even if this threshold is lower than the usual balance of probabilities test to discharge a legal burden, it is still quite some way higher than inherent incredibility, which is arguably an even lower threshold than a reasonable possibility. This threshold also makes sense because then there is concordance between the situation where the Prosecution bears the legal burden, and where it is the Defence which bears the legal burden:

1. Where the Prosecution bears the legal burden to prove elements of offence – evidential burden is discharged if it has adduced evidence, if believed, sufficient to prove the elements of the offence beyond reasonable doubt.
2. Where the Defence bears the legal burden to prove a defence or rebut a presumption – evidential burden is discharged if it has adduced evidence, if believed,²³Note that here, what is to be believed is the evidence or testimony adduced, not the Defence’s overall assertion that the defence is made out or that the presumed fact is untrue. Different pieces of adduced evidence or testimony could be believed but yet the Defence’s overall assertion could well remain not more likely true than untrue. sufficient to prove the defence or rebut the presumed fact on the balance of probabilities.

In addition, in the context of presumptions in the MDA, there is arguably another equally important reason why the threshold should not merely be whether the Defence is inherently incredible. The presumptions were introduced “precisely to address the difficulty of [the police and the Prosecution] proving an accused person’s subjective state of knowledge”.²⁴Parliamentary Debates Singapore: Official Report, vol 94, “Oral Answers to Questions – Review of Misuse of Drugs Act” (8 July 2019) (Mr Amrin Amin, Senior Parliamentary Secretary of Ministry for Home Affairs). To require the Prosecution to positively adduce evidence regarding an accused’s state of mind so long the Defence’s case is not inherently incredible seems to not be consistent with explicit legislative intent.

Putting aside whether the correct threshold should be one of inherent incredibility, the other difficulty is that the Court appears to have essentially equated the Defence’s discharge of its evidential burden with its discharge of its legal burden. This is especially apparent in Beh Chew Boo. After concluding that the accused’s account was not inherently incredible,²⁵Supra n 14 at (64)-(70). the Court held that the evidential burden fell on the Prosecution, which it failed to discharge in deciding not to call a material witness.²⁶Ibid at (71)-(76). The Court then, without more, concluded that the accused had successfully rebutted the relevant presumption.²⁷Ibid at (80)-(81). That approach is somewhat abstruse given that the discharge of evidential burden vis-à-vis an issue should merely mean that that issue remains to be decided.²⁸Cross and Tapper on Evidence, supra n 21 at 128. See also Cross on Evidence, supra n 22 at (7015). In fact, the concept of evidential burden was created to cater to jury trials, where judges had to decide which specific issues to instruct jury members to reach a finding of fact on.²⁹Ibid at 128. Thus, there is reason to question the concept’s utility in bench trials. Where an accused has discharged his evidential burden in relation to a presumption, he ultimately still has a legal burden to show that on the totality of evidence, the presumed fact is disproved on a balance of probabilities.³⁰Cross on Evidence, supra n 64 at (7210) and Adrian Keane & Paul McKeown, The Modern Law of Evidence, 12^th ed (Oxford University Press, 2018) at 87-88. In that connection, the Prosecution can seek to demonstrate that this legal burden is not discharged not only by adducing its own evidence (which would include calling of witnesses), but also simply by showing that the Defence’s account in itself is not more likely true than not.³¹This would be a corollary of the fact that where the Prosecution bears the legal burden to prove elements of an offence beyond reasonable doubt, the Defence can either adduce its own evidence and convince the fact-finder that there is a reasonable doubt on the totality of evidence, or it can simply seek to discredit the Prosecution’s evidence to show that a reasonable doubt exists within the Prosecution’s case (see PP v GCK (2020) 1 SLR 486 at (134)-(145)). In other words, even assuming an accused has discharged his evidential burden, the presumption may in the end not be rebutted even if the Prosecution had decided not to call a material witness.

It may thus be worth reconsidering these issues at some future opportunity. Regardless, this is definitely a particularly difficult area of law, and a delicate balance will have to be struck between: a) the inherent difficulties of the police and the Prosecution proving an accused’s subjective state of mind,³²Supra n 24. b) the inherent difficulties of an accused proving a negative state of knowledge,³³Nabill, supra n 1 at (92). c) the fact that the MDA offences potentially attract very harsh punishment, d) the fact that these offences inflict a great deal of harm on our society,³⁴Chan Sek Keong, “The Criminal Process – The Singapore Model” (1996) Singapore Law Review 433 at 497-498. and e) the need for courts and lawmakers to be on guard against manufactured defences (by accused persons and drug syndicates).³⁵PP v Muhammad Farid bin Mohd Yusop (2015) 3 SLR 16 at (48)-(49), Parliamentary Debates Singapore: Official Report, vol 87 at col 407 (18 May 2010) (Mr K Shanmugam, Minister for Home Affairs) and Report of the Penal Code Review Committee (August 2018) at 259-263.

Conclusion

In this past decade, our courts have had occasion to stress the role of prosecutors as Ministers of Justice. These should not necessarily be interpreted as suggesting that prosecutors had previously not been acting as Ministers of Justice, but rather, as general reminders in line with the crystallisation and fine-tuning of specific aspects of the Prosecution’s role. If anything, prosecutors have been acting as Ministers of Justice since the institution of Prosecution took root in Singapore. Prosecutors have also no need to be too concerned, for example, that fuller disclosure may give guilty accused persons added arsenal or technicalities to exculpate themselves. If the Prosecution is convinced in a case that there is overall a reasonable prospect of conviction despite potential weaknesses against its case arising from some unused material, then it is simply a matter of good advocacy to be candid and open to the fact-finder at the trial about these weaknesses, and advocate (with vigour) on why, on the totality of evidence, the accused should still be convicted.³⁶See the quote by Jonathan Crow QC on persuasive advocacy in Alan Paterson, Final Judgment: The Last Law Lords and the Supreme Court (Hart Publishing, 2013) at 43. As has been recently alluded to in Parliament, our courts are well able to carefully scrutinise all evidence in a case to arrive at a just decision.³⁷Parliamentary Debates Singapore: Official Report, vol 94, “Oral Answers to Questions – Review of Misuse of Drugs Act” (8 July 2019) (Mr Amrin Amin, Senior Parliamentary Secretary of Ministry of Home Affairs).

Finally, in the discourse on Prosecution’s duty of disclosure and decision to call witnesses, much has been said about how better resourced the Prosecution is compared to the Defence. While that may be true vis-à-vis the Prosecution as an institution, when the actual ratio of prosecutors and police officers to criminal cases every year is considered,³⁸Parliamentary Debates Singapore: Official Report, vol 95, “Review of the Case of Parti Liyani v Public Prosecutor (2020) SGHC 187” (4 November 2020) (Mr K Shanmugam, Minister for Home Affairs and Minister for Law). the disparity may not be as stark as one might think. What is also evident is that the Prosecution’s role, as a Minister of Justice, is a demanding and sui generis one.³⁹Changing Role of the Modern Prosecutor, supra n 8 at (1.1.12). Thus, it is heartening to see many of our lawmakers joining hands to recognise the challenges faced by the Prosecution, and in affirming its paramount contributions towards advancing a criminal justice system that works for Singapore.⁴⁰See generally Parliamentary Debates Singapore: Official Report, vol 95, “Review of the Case of Parti Liyani v Public Prosecutor (2020) SGHC 187” (4 November 2020).