Conviction for Sexual Assault on Minors Based on Sole Testimony of the Victim

STS 218/2026, of 17 March, delivered in cassation appeal 4722/2023, provides a precise synthesis of the Supreme Court's doctrine on the evidential value of a minor victim's testimony in sexual assault offences under Article 181 of the Criminal Code. The ruling is significant not only for what it confirms — the sufficiency of sole testimony — but also for the way it recalls the requirements that must be met before a refusal of evidence can be reviewed on cassation.

The sole-victim-testimony doctrine

The Supreme Court reiterates in this judgment a well-established doctrine: the victim's statement, even where it is the only direct evidence of guilt available, constitutes sufficient evidence to support a conviction when the trial court assesses it rationally and properly reasons its credibility. There is no rule in Spanish criminal procedure requiring multiple witnesses or an additional corroborating piece of evidence.

The basis for this position lies in the distinction between the presumption of innocence as a fundamental right — which requires sufficient incriminating evidence, rationally assessed — and a hypothetical corroboration rule that the legislature has not enacted. The LECrim does not require the court to have more than one witness in order to convict: what it requires is that the conviction be the result of a reasonable assessment of the body of evidence heard with due guarantees.

Reasoning and rationality: the requirements of cassation review

The sufficiency of sole testimony does not mean that any victim's statement is enough to convict. The Supreme Court has developed a standard of rational assessment that the trial court must observe and set out in its judgment. That standard includes, among other parameters, the internal coherence of the account, its persistence throughout the proceedings and the absence of spurious motivations that could undermine its credibility.

The cassation review is, in any event, external and limited. The Criminal Chamber of the Supreme Court cannot substitute the direct perception of the trial court — which witnessed the taking of evidence — with its own assessment. What it can do is verify that the reasoning is sufficient and that the conclusions reached are not arbitrary or manifestly irrational. If the judgment of the trial court clears that threshold of rationality, the conviction must be upheld even if the cassation court might have assessed the evidence differently.

Refusal of evidence: formal and substantive requirements

STS 218/2026 also addresses the ground based on the refusal of evidence proposed by the defence. The Chamber recalls that this cassation ground requires the cumulative presence of two categories of requirements:

The formal requirements consist, essentially, in having objected in due time and form before the court that refused the evidence. The objection is not a mere formality: it is the procedural condition that preserves the complaint for subsequent review. A party that tacitly accepts the refusal of evidence or fails to renew it at the appropriate procedural stage forecloses the possibility of relying on it as a cassation ground.

The substantive requirements are more demanding. It is not enough that the refused evidence was relevant — that is, connected to the subject matter of the proceedings: it must have been necessary. Necessity means that its taking could have altered the outcome, so that its absence caused the appellant actual defencelessness. Evidence that, had it been taken, would not have changed the guilty verdict does not satisfy this condition, and its refusal does not succeed as a cassation ground even where the proposal was formally correct.

Article 181 CP and the presumption of incapacity to consent

The facts adjudicated in STS 218/2026 fall within the offence defined in Article 181 of the Criminal Code, which penalises sexual acts performed with persons under the age of sixteen. The reinforced criminal protection afforded by that provision rests on a legal presumption: minors below that age lack the maturity required to validly consent to sexual relations with adults, regardless of what they may have expressed at the time.

This presumption has a significant evidential effect: the defence cannot invoke the minor's consent as a ground of atypicality or as a circumstance excluding criminal liability. The evidential debate therefore shifts to establishing the reality of the acts — territory in which the victim's testimony becomes central — and, where applicable, to the presence of circumstances modifying criminal responsibility.

The relationship of trust as an aggravating circumstance

Where the perpetrator maintains a relationship of trust, authority or kinship with the victim, the Criminal Code provides for aggravated offences whose application STS 218/2026 confirms. The rationale for the aggravation lies in the particular reproach that attaches to the exploitation of a bond that should have protected the minor: the perpetrator not only violates the victim's sexual inviolability but instrumentalises the trust the victim had placed in him to commit the offence.

From a defence perspective, the applicability of these aggravated offences requires the prosecution to have proved them at trial with the same rigour as the basic offence. The aggravation cannot be presumed or derived from the mere family or emotional relationship: it must be proved that the perpetrator acted by effectively exploiting that position.

Practical implications of the judgment

STS 218/2026 consolidates a delicate balance between the protection of the minor victim and the guarantees of the criminal process. For a person investigated or charged with an offence under Article 181 CP, the judgment underlines that the defence must focus on a rigorous analysis of the evidential assessment carried out by the trial court — verifying whether the reasoning is sufficient and whether the conclusions are reasonable — and on the correct use of the procedural instruments available to challenge decisions on evidence.

Raising a timely, proper objection to any refusal of evidence is not a dispensable formality: it is the indispensable precondition for relying on that ground at later stages. Equally, a proposal of evidence must be accompanied by justification of its necessity — not merely its relevance — in order to preserve the complaint against an eventual refusal.