Circumstantial Evidence: Conviction Without Direct Proof and the Presumption of Innocence

One of the most frequent questions in criminal practice is whether someone can be convicted when there is no direct evidence of their involvement: no eyewitness, no confession, no recording showing the act. The Supreme Court's answer is nuanced but clear: conviction is possible, including through what is known as circumstantial evidence, provided that demanding requirements are met and the court's inference is duly reasoned. This is recalled by the Supreme Court in its judgment 355/2026 of 21 May (appeal 4044/2023), in a matter concerning an offence against sexual freedom committed against a person deprived of awareness, where there was no direct evidence of the act. We comment below on the evidentiary doctrine, for informational purposes and without going into the details of the case.

What circumstantial evidence is

Circumstantial evidence — also called indirect evidence or evidence by presumptions — does not directly establish the fact to be proved, but other facts (the indicia) from which, through logical reasoning, the court deduces that principal fact. As against direct evidence, which shows the fact immediately — the witness who saw what happened, the document recording it — circumstantial evidence operates by inference: it starts from established data and, linking them, reaches a conclusion on the matter in dispute, usually authorship or participation.

A common misconception should be dispelled. Circumstantial evidence is not evidence of a lower category, nor a substitute for direct evidence. It is a fully valid means of proof and, for many offences, the only one actually available: consider acts committed in secret, without witnesses, or against persons unable to perceive what happened. What distinguishes it from mere suspicion is its subjection to a strict rationality review, which is precisely what turns it into incriminating evidence capable of grounding a conviction.

The requirements set by the Supreme Court

The Supreme Court, in its judgment 355/2026 of 21 May, recalls the conditions that must be present for circumstantial evidence to ground a conviction without breaching the presumption of innocence. In essence, they are the following:

• Plurality of indicia. As a general rule, a single isolated indicium is not enough. The strength of circumstantial evidence arises from the convergence of several data pointing in the same direction.
• Fully established indicia. Each of the basic facts must be proved with certainty; an inference cannot be built on doubtful indicia or, worse still, on other unestablished indicia.
• A coherent, seamless inference. The reasoning linking the indicia to the incriminating conclusion must lead to it so solidly that it blocks any other reasonably possible hypothesis. If the deduction leaves open reasonable alternatives compatible with innocence, it is not sufficient.
• Express reasoning. The court must explain the reasoning: why guilt follows from those indicia and not from another interpretation. Reasoning is not an ornament, but the safeguard that allows the rationality of the inference to be verified.

The underlying idea is that a conviction should rest not on intuition, but on explained and reviewable reasoning that rationally excludes the alternative explanations compatible with innocence.

Combining indicia and expert evidence

A particularly relevant aspect of the doctrine recalled by the Supreme Court is the role of expert evidence in combination with the indicia. The judgment stresses that the combination of circumstantial evidence with expert evidence may rebut the presumption of innocence even where there is no direct evidence and no witnesses to the act.

In practice, this means that the experts' report — medical, forensic or specialists in various fields — may supply the technical datum that, added to the established indicia, closes the reasoning and excludes the alternative hypotheses. It is not that the expert evidence replaces the inference, but that it reinforces it: the whole — plural, established indicia plus expert conclusions — leads coherently to guilt. For that reason, in offences committed without eyewitnesses, the quality and solidity of the expert evidence acquire decisive weight, both for the prosecution and for the defence.

Review of the inference on cassation

How far can the Supreme Court review a conviction based on indicia? Cassation is not a third instance that re-assesses all the evidence as if it were a new trial. What the Supreme Court reviews is the rationality of the evidentiary reasoning: that the indicia are in fact established, that they are plural and that the inference linking those indicia to the incriminating conclusion is reasoned and logical.

The review focuses above all on the solidity of the inference. If the trial court's deduction is open, too weak or admits reasonable alternatives compatible with innocence, the conviction does not respect the presumption of innocence and must be reviewed. Conversely, if the inference is closed and coherent — so that it blocks the reasonable alternative hypotheses — and is duly explained, the Supreme Court confirms that the fundamental right has been respected, even though there was no direct evidence. The cassation examination is therefore an examination of method and logic, not a fresh assessment of the facts.

What it means for the presumption of innocence

The doctrine recalled by the Supreme Court strikes a balance. On the one hand, the presumption of innocence remains fully operative: no one may be convicted on the basis of mere conjecture, of a single equivocal indicium or of an inference that leaves the field open to other explanations. On the other hand, that presumption does not always require direct evidence: to hold otherwise would lead to the systematic impunity of offences committed without witnesses, which are numerous.

The meeting point is the requirement of quality in the reasoning. Circumstantial evidence respects the presumption of innocence where, starting from plural and established indicia, it leads seamlessly to guilt and rationally excludes the reasonable alternatives, all with reasoning that allows its review. Where any of those elements fails, the reasonable doubt must be resolved in favour of the accused.

Why this matters for the defence

For anyone facing a charge based on indicia, understanding this doctrine is essential. The defence does not merely deny the existence of direct evidence — which frequently is absent — but is built on the critical analysis of the inference: questioning whether the indicia are really established, showing that they are not as plural or convergent as the prosecution claims and, above all, demonstrating that there is at least one reasonable alternative hypothesis compatible with innocence that the reasoning fails to rule out.

Equally decisive is the scrutiny of the expert evidence: examining the methodology used, the limits of the report and its true scope, as well as the strength of the link between the expert conclusion and the indicia. The presumption of innocence requires the inference to be closed; the work of the defence often consists in showing that it is not. This commentary is for informational purposes and does not constitute legal advice: each case requires an individualised study of the evidence and of its rationality.