Maqubela v The State

Thandi Sheryl Maqubela (the appellant) was convicted by the Western Cape High Court of murdering her husband, Patrick Ntobeko Maqubela (the deceased), and was also convicted of forgery and fraud relating to the deceased's will. She was sentenced to 15 years' imprisonment on the murder count and 3 years on each of the other counts (to run concurrently), resulting in an effective sentence of 18 years' imprisonment. Her co-accused, Vela Mabena, was found not guilty and discharged. The appellant pleaded not guilty to all charges and denied murdering the deceased by suffocation (as alleged by the State) or any other means, contending that the deceased died of natural causes. The State presented expert medical evidence on cause of death, as well as evidence suggesting guilty consciousness and mendacity on the part of the appellant.

• Whether the medical evidence established the actus reus of murder
• Whether expert medical evidence should be assessed according to the scientific measure of proof (scientific certainty) or the judicial measure of proof (balance of probabilities)
• Whether evidence of an accused's mendacity and guilty consciousness alone could prove murder in the absence of proof of an unlawful killing
• Whether the trial court correctly applied the rules of inferential reasoning from R v Blom
• Whether the trial court erred in applying the minority judgment in R v Mlambo to treat mendacity as independent evidence proving the actus reus of murder

The appeal was upheld. The conviction and sentence of the appellant on count 1 (murder) were set aside and replaced with a verdict of not guilty and discharged on the charge of murdering Patrick Ntobeko Maqubela.

When assessing expert medical evidence on cause of death in criminal proceedings, courts must apply the judicial measure of proof (balance of probabilities) and not the scientific measure of proof (scientific certainty). Expert witnesses may assess likelihood in terms of scientific certainty, but courts must assess where the balance of probabilities lies on a review of the whole evidence. Evidence of an accused's mendacity and guilty consciousness cannot, without proof of an unlawful killing, establish the actus reus of murder beyond reasonable doubt. When applying inferential reasoning, the inference of guilt must be consistent with all proved facts, and if the evidence establishes that the deceased probably died of natural causes, an inference of unlawful killing cannot reasonably be drawn, regardless of evidence showing guilty consciousness.

The court noted that counsel for the appellant conceded that if it had been shown that the deceased had not died of natural causes, the mendacity and actions of the appellant after the event were such that her guilt would have been established. The court indicated that it did not need to consider the legal issue of whether the trial court erred in its reliance upon the minority judgment of Malan JA in R v Mlambo 1957 (4) SA 727 (AD) in concluding that evidence of consciousness of guilt could, in the absence of other evidence, prove an unlawful killing beyond reasonable doubt, as the finding on the medical evidence was dispositive of the appeal.

This case is significant in South African criminal law for clarifying the critical distinction between the scientific measure of proof (scientific certainty) and the judicial measure of proof (balance of probabilities) when assessing expert medical evidence in criminal trials. It established that courts must not demand scientific certainty from expert witnesses but must assess expert evidence on the balance of probabilities. The case also reinforces the principle that evidence of guilty consciousness and mendacity, while relevant, cannot substitute for proof of the actus reus of murder. It serves as an important reminder that in applying the rules of inferential reasoning (R v Blom), any inference drawn must be consistent with all proved facts, and the inference of guilt must be the only reasonable inference available, not merely a possible one.