Brief Summary

Murder — Cause of death — Expert medical evidence — Trial court's erroneous application of scientific measure of proof — Appellant convicted of murdering her husband, with the trial court relying on circumstantial evidence of guilt and mendacity — Appeal upheld on the basis that the medical evidence did not conclusively establish the cause of death, and the proper judicial measure of proof indicated a probable natural cause — Conviction and sentence set aside, and appellant found not guilty.

Comprehensive Summary

Summary of Judgment

1. Introduction

This was a criminal appeal in the Supreme Court of Appeal of South Africa against a conviction for murder. The appellant was Ms Thandi Sheryl Maqubela, who had been accused 1 in the trial court. The respondent was the State.

The matter originated in the Western Cape Division of the High Court, Cape Town, where Murphy J (sitting as court of first instance) convicted the appellant on three counts, namely murder (count 1), forgery (count 2), and fraud (count 3). The appellant received a sentence of 15 years’ imprisonment on the murder count and three years’ imprisonment on each of the forgery and fraud counts, with the sentences on counts 2 and 3 ordered to run concurrently with each other, resulting in an effective sentence of 18 years’ imprisonment.

The appellant’s co-accused, Mr Vela Mabena, who was charged only with murder, was acquitted. The appeal before the Supreme Court of Appeal was pursued only against the murder conviction and was brought with the leave of the trial judge.

The general subject-matter of the dispute concerned whether the State proved, beyond reasonable doubt, that the deceased (the appellant’s husband, Mr Patrick Ntobeko Maqubela) died as a result of an unlawful killing (alleged by suffocation) rather than natural causes, in circumstances where the trial court placed substantial weight on both (i) expert medical evidence regarding the cause of death and (ii) evidence of the appellant’s “guilty consciousness” and mendacity following the death.

2. Material Facts

The deceased was the appellant’s husband. The State alleged that the appellant murdered the deceased, including by suffocation, although the appellant denied murdering him by suffocation or by any other means. The appellant’s defence, in substance, was that the deceased died of natural causes.

A central factual feature of the case was the presence of conflicting expert medical opinion on the cause of death. The State called Dr Mfolozi, a specialist pathologist, while the defence called Professor Saayman, also a specialist pathologist. The trial court conducted a detailed examination of their evidence, including post-mortem findings and what could or could not be excluded on that basis.

The Supreme Court of Appeal treated as material the trial court’s own finding that an inference of sudden death by reason of cardio-pathology would be consistent with the proven medical facts. The trial court nonetheless ultimately described the medical evidence as “inconclusive” on the cause of death, a characterisation that became central to the appeal.

The medical evidence was relevant not only to whether suffocation could be supported, but also to whether natural causes could be excluded. The Supreme Court of Appeal emphasised that, on the record as analysed, Professor Saayman’s evidence was that, on a probability assessment, the pathology in the deceased’s heart presented a substantially greater likelihood of being causative of death, encapsulated in his view that “the probabilities are that his heart killed him,” and that a pathologist should “first and foremost” consider natural causes as the cause of death in this case.

A further material factual component—separate from medical causation—was that the trial court relied heavily on evidence of the appellant’s post-event conduct, which it treated as demonstrating consciousness of guilt, together with findings of the appellant’s considerable mendacity. The Supreme Court of Appeal noted that the trial court regarded these features as pivotal to whether murder could be inferred despite its view that the medical evidence did not provide a definitive cause of death.

Although the appellant was also convicted of forgery and fraud relating to a purported will, the Supreme Court of Appeal’s judgment (as provided) addressed the appeal only in relation to count 1 (murder), and the material facts were confined to those bearing on the cause of death and the permissibility of inferring unlawful killing beyond reasonable doubt.

3. Legal Issues

The central legal questions were whether the trial court erred in its treatment of the expert medical evidence on cause of death, and whether—on a proper approach to the evidence—murder was proved beyond reasonable doubt.

More specifically, the Supreme Court of Appeal had to determine whether the trial court wrongly evaluated the medical evidence by applying an inappropriate standard of proof associated with scientific certainty, rather than the judicial measure of proof requiring an assessment of probability within the criminal standard (proof beyond reasonable doubt on the totality of evidence, including inferential reasoning).

The dispute involved both questions of law and the application of law to fact. It raised a legal issue concerning the correct approach to expert scientific evidence, including the distinction between the scientific and judicial measures of proof, and it raised an inferential-reasoning question under the principles governing circumstantial evidence, namely whether the proved facts excluded every reasonable inference other than guilt.

A further issue raised in the grounds of appeal (though ultimately not decided as necessary for the outcome) concerned whether the trial court was correct to rely substantially on the minority judgment in R v Mlambo 1957 (4) SA 727 (AD) to treat the appellant’s lies and guilty consciousness as independent circumstantial evidence establishing the actus reus of murder in the absence of other proof of unlawful killing.

4. Court’s Reasoning

The Supreme Court of Appeal identified a critical analytical error in the trial court’s handling of the medical evidence. It held that the trial court failed properly to appreciate the distinction between the scientific measure of proof (scientific certainty) and the judicial measure of proof (probability assessment). In doing so, the trial court reached a logically inconsistent position: it accepted that sudden death due to cardio-pathology was consistent with the proven medical facts, but still concluded that the medical evidence was “inconclusive” as to cause of death.

Relying on Michael & another v Linksfield Park Clinic (Pty) Ltd & another 2001 (3) SA 1188 (SCA), the Supreme Court of Appeal reiterated that experts tend to speak in terms of scientific certainty, whereas courts must assess where the balance of probabilities lies on a review of the whole evidence. The judgment also referenced the warning in Dingley v The Chief Constable, Strathclyde Police 200 SC (HL) 77 about the risk of a judge being “seduced” into applying the expert’s scientific standards rather than the judicial standard of proof.

Applying those principles, the Supreme Court of Appeal reasoned that certain formulations in the evidence and in the trial court’s summary—such as statements that suffocation and natural or other undetected causes were “equally possible”—were framed in the context of scientific certainty, not the court’s probabilistic task. When the appropriate judicial approach was applied, Professor Saayman’s evidence was not that the cause of death was unknowable in a court’s sense, but rather that natural causes were the more probable explanation, given the heart pathology and associated probabilities.

The Supreme Court of Appeal contrasted the foundations of the two experts’ opinions as reflected in the record. It accepted that Professor Saayman’s conclusion that natural causes probably explained death was based on objective medical facts, logical reasoning, and probabilities. By contrast, the judgment highlighted concessions made by Dr Mfolozi, including that he had not taken sections of all of the heart and therefore could not exclude, with complete certainty, focal viral myocarditis that could in extreme cases be fatal, and that it was possible he may have missed such a condition.

Having concluded that natural causes were probably the cause of death, the Supreme Court of Appeal treated this as decisive for the inferential enquiry the trial court had characterised as “pivotal.” The trial court had posed the question whether a concatenation of conduct showing consciousness of guilt, in the absence of proof of a probable or certain cause of death, could justify inferring murder beyond reasonable doubt. On the Supreme Court of Appeal’s approach, the premise of “absence of proof of a probable” cause of death fell away: the proper assessment of the medical evidence yielded a probable natural cause.

The court then applied principles of inferential reasoning, referring to R v Blom 1939 AD 188. It accepted that the trial court correctly stated that the proved facts had to exclude every reasonable inference other than guilt, but emphasised the primary rule that the inference of guilt must be consistent with all the proved facts. Given the acceptance that natural death was a probable cause, the Supreme Court of Appeal held that, even taking the appellant’s mendacity and guilty consciousness into account, unlawful killing was not the only reasonable inference.

Because that conclusion disposed of the appeal, the Supreme Court of Appeal stated that it was unnecessary to consider the further legal debate about whether the trial court erred in relying on the minority view in R v Mlambo regarding the evidential use of lies or guilty consciousness as independent proof of the actus reus.

The judgment also noted a concession by counsel for the appellant: if it had been shown that the deceased did not die of natural causes, the appellant’s post-event conduct and mendacity would have been such that guilt would have been established. However, given the court’s conclusion that natural causes probably explained the death, it held that an inference of unlawful killing could not reasonably be drawn, and that the trial court had incorrectly relied on guilty conduct “without more” to prove murder beyond reasonable doubt.

5. Outcome and Relief

The Supreme Court of Appeal upheld the appeal.

It set aside the appellant’s conviction and sentence on count 1 (murder) and substituted an order acquitting the appellant on that count, expressed as a finding of not guilty and discharged on the murder charge relating to Mr Patrick Ntobeko Maqubela.

No costs order is recorded in the provided judgment text.

Cases Cited

Michael & another v Linksfield Park Clinic (Pty) Ltd & another 2001 (3) SA 1188 (SCA).

Dingley v The Chief Constable, Strathclyde Police 200 SC (HL) 77.

R v Mlambo 1957 (4) SA 727 (AD).

R v Blom 1939 AD 188.

S v Maqubela & another 2014 (1) SACR 378 (WCC).

Legislation Cited

No legislation is cited in the provided judgment text.

Rules of Court Cited

No rules of court are cited in the provided judgment text.

Held

The Supreme Court of Appeal held that the trial court materially erred by treating the expert medical evidence through the lens of scientific certainty and, as a result, wrongly characterised the cause of death as “inconclusive” in the judicial sense.

On a proper judicial assessment of the expert evidence, the deceased’s death was probably due to natural causes, which meant that unlawful killing was not established as the only reasonable inference consistent with the proved facts.

Even allowing for evidence of the appellant’s mendacity and apparent consciousness of guilt, those features could not, in the circumstances where natural death remained the probable cause, sustain a conviction for murder beyond reasonable doubt. The murder conviction was therefore set aside and replaced with an acquittal on count 1.

LEGAL PRINCIPLES

A court assessing expert scientific or medical evidence must distinguish between the scientific measure of proof (scientific certainty) and the judicial measure of proof (probability assessment on the totality of evidence). The judicial function is not to demand scientific conclusiveness, but to determine, applying the legal standard, what is probable and what inferences may properly be drawn from all the proved facts.

In cases depending on circumstantial evidence, the inferential rules in R v Blom 1939 AD 188 apply, including that the inference sought must be consistent with all the proved facts and that the proved facts must exclude every reasonable inference other than the inference of guilt. Where the medical evidence properly evaluated indicates that natural causes are a probable explanation, an inference of unlawful killing will not be the only reasonable inference, notwithstanding evidence suggestive of guilty consciousness or mendacity.

Where there is a probable natural cause of death on the medical evidence, reliance on an accused’s post-event conduct and lies “without more” cannot convert an otherwise unproven actus reus of murder into proof beyond reasonable doubt.

Maqubela v S (821/2015) [2017] ZASCA 137; 2017 (2) SACR 690 (SCA) (29 September 2017)