What the Dani Alves ruling lets us conclude (on criminal evidence, and on why private investigation in criminal proceedings is —and should be— possible)
Few recent proceedings have placed Spain's criminal evidentiary system under greater public strain than the Alves case. A conviction by the Provincial Court of Barcelona (February 2024, four and a half years' imprisonment); a unanimous acquittal by the High Court of Justice of Catalonia (TSJC) (28 March 2025) for insufficient evidence; and, as of today, cassation appeals by the Public Prosecutor's Office and by the private prosecution still pending before the Supreme Court, which will have the final word. This article does not set out to relitigate the case or correct any court: it sets out to draw, with the clinical detachment the matter demands, the conclusions that the two rulings already handed down allow us to reach about how criminal evidence works — and about the role, larger than commonly believed, that investigation plays in it.
One preliminary clarification that the TSJC itself put in writing, and which we make our own: acquitting for insufficient evidence is not the same as stating that the complainant failed to tell the truth. The presumption of innocence is not a verdict about people; it is a standard about evidence. With that premise established, four conclusions follow.
1. A single testimony can convict — but it is subjected to a test, and the test grew stricter
Settled case law accepts that a victim's statement can amount to sufficient evidence for conviction, even standing alone, provided it passes a three-part test: persistence in the accusation, the absence of improper motives, and plausibility corroborated by peripheral evidence. The Alves case dramatized, as no other has, the critical phase of that test: what happens when the parts of the account that can actually be checked against objective evidence fail that check.
The Provincial Court convicted while acknowledging discrepancies between segments of the testimony and the video recordings, but it considered the core of the account reliable — what happened where there were no cameras. The TSJC, unanimously, took the opposite view: if the account differs markedly from the recordings on its verifiable portion, the reliability of the whole is compromised, and the testimony cannot be sliced up so as to preserve as true precisely the part that admits no verification. It will be for the Supreme Court to settle the doctrine on that disagreement — the Public Prosecutor's Office argues in its appeal that the TSJC's assessment was not rational. But the structural lesson already holds for every practitioner: credibility is won or lost on the checkable periphery. What the cameras, the timings, and the witnesses say about the verifiable minutes determines the weight of the minutes no one saw.
2. Modern criminal evidence is a battle over peripheral facts — and that battle is pure investigation
Notice, reader, where this case was actually decided at both instances: in a nightclub's recordings, in the minute-by-minute reconstruction of one early morning, in the forensic biological reports, in the consistency between the different accounts and the objective trail. In other words: in material that someone had to locate, preserve, put into chronological order, and produce before it degraded. A venue's cameras get overwritten within days or weeks; witnesses scatter; devices get lost. The window for securing the verifiable periphery of a set of facts is measured in hours.
That is the first operational lesson of the case, valid for defence teams and private prosecutions alike: in a proceeding that will be decided by the contrast between the account and objective reality, whoever arrives late to preserve that objective reality litigates blind. The urgent preservation of CCTV footage, the early identification of eyewitnesses, and a documented chronological reconstruction are not luxuries reserved for the famous client: they are the infrastructure of any serious defence — or prosecution. And I do not say this at second hand, as will become clear at once.
A due disclosure: in this case, that work was ours
Before going any further, the reader deserves to know where I am writing from. The defendant's defence team commissioned this firm to investigate what happened that early morning at the nightclub: fact-verification and a video reconstruction of the verifiable sequence. This is a matter of public record — and it appears in the acquittal itself, which expressly relies on that work in setting out one of its factual findings:
"We conclude that the complainant went voluntarily to the toilet area of the [reserved area], with the intention of being with the defendant in a more intimate space. And that, from where she was standing, she could tell that she was heading toward an enclosed space, possibly a bathroom, as follows from the documentary evidence submitted by the defence, which shows the interior from the point where the complainant entered (folios 148 et seq. of the video expert report and reconstruction of the events prepared by Mr. Francisco Marco, which has not been challenged)." (STSJ Catalonia 109/2025, of 28 March)
Two details in that passage condense everything this series has been teaching. The first: what the court relies on is not an opinion but a verifiable reconstruction — a video expert report that lets the judges see the space and the sequence for themselves, instead of having to take anyone's word for it. This is the checkable periphery we have been discussing, turned into technical support. And the second, which I allow myself to underline because it is the quiet culmination of twenty-five entries: "which has not been challenged." In the most scrutinized criminal proceeding of the decade, against the best prosecuting teams available, the work reached the courtroom built in such a way that the other side could not even find an angle from which to attack it. Evidence designed to survive challenge sometimes achieves something better still: not being challenged at all.
I do not cite this involvement as a badge of honour, but as a direct source of knowledge for what this article argues: that the verifiable periphery of a set of facts is preserved within a window of hours, that reconstructing a New Year's early morning is a race against dispersal, and that all of that work was done — and could only be done — within the exact perimeter the law sets for the private investigator, which is what we turn to next. The weighing of the evidence is a matter for the courts, and to them we defer; the lawful, timely gathering of the material for comparison, by contrast, is our trade, and it is to that trade that I bear witness here.
3. Yes, investigation is possible in criminal matters — the exact map
And here is the conclusion that gives this entry its title, because the case disproves a cliché this series has already challenged: the idea that "in criminal matters, the investigator can't do anything." The real map, which I set out in Chapter 6 of my Manual jurídico, is more nuanced and far more useful:
What is forbidden: investigating publicly prosecutable offences as a parallel inquiry running alongside the state's own. The monopoly established by STS 908/2016 remains intact, and with it the duty to report any publicly prosecutable offence one becomes aware of.
What is permitted — and decisive: first, the investigation of offences that are prosecutable only at the request of a party, when commissioned by those with standing to bring the criminal proceedings — a category that includes, let us not forget, offences against sexual freedom, which require a complaint from the aggrieved person (art. 191 CP). Second, and for every type of proceeding, the verification of facts in the service of the right to a defence through evidence (art. 24.2 CE): locating witnesses, obtaining and preserving lawful recordings, reconstructing timelines, documenting the checkable periphery of an account. That is not usurping the investigation of the offence itself, which belongs to the judge and the police: it is building, within the bounds of the law, the comparison material that the court will later weigh. Exactly the kind of work that decided — one way at first instance, the opposite way on appeal — the proceeding we have been discussing.
What is non-negotiable: the usual limits. No harassing witnesses or complainants, no intrusion into reserved spheres, no provocation, and use exclusively for the proceedings. In matters as sensitive as sexual offences, moreover, defence-side investigation demands a reinforced code of conduct: the fact is verified, the person is never harassed. The line between investigating a timeline and pressuring a complainant is not thin: it is a chasm, and whoever crosses it does not merely commit an unlawful act — they destroy the very defence they claimed to be serving.
4. The uncomfortable conclusion: criminal proceedings reward whoever investigates better, and that is a challenge to everyone
If the two rulings teach us anything, it is that the criminal outcome depends critically on the quality of the comparison material available. That observation admits a partisan reading — the defence or prosecution that invests in rigorous investigation litigates with an advantage — and an institutional one that should not be brushed aside: a system in which the verification of the factual periphery carries so much weight needs that work to be done promptly, properly, and by professionals subject to legal oversight. This is the argument I have been making in academic settings in favour of fully integrating private investigation into criminal proceedings, as every legal system in our surrounding region does: not to privatize justice, but so that the equality of arms guaranteed by art. 24 CE becomes something more than a metaphor.
The Supreme Court will have the last word on the case. The conclusions about the evidence, however, have already been stated: testimony is weighed against verifiable reality, verifiable reality has to be actively preserved, and doing so with method — within the law, with scrupulous respect for everyone involved — is not a tactical option. It is the modern way of exercising the right of defence.
The investigator's legal status in criminal proceedings, and offences prosecutable only at the request of a party, are examined in Chapters 6 and 15 of "Manual jurídico sobre los servicios de detective privado y sus informes" (Tirant lo Blanch, 2025). Método 3 has provided fact-verification and evidentiary-support services to defence teams and prosecutions since 1985. Truth has a method.
Closing of the series
This compilation brings together 21 articles of legal and professional commentary on private investigation, evidence, privacy, business, and artificial intelligence. The pieces are prepared as independent entries for publication on the Método 3 blog.
Truth has a method.