The validity of an Internal Investigation as the basis for an acquittal
Analysis of Judgment No. 1734/2026 of 16 February 2026 handed down by the Provincial Court of Madrid (30th Criminal Division).
This commentary analyses the recent Judgment No. 1734/2026 of 16 February 2026 handed down by the Madrid Provincial Court, which rules on the appeal lodged by the private prosecutor against an acquittal in a trial concerning a minor offence involving alleged threats.
The Civil and Preliminary Investigation Section of the Collado Villalba Magistrates’ Court, Court No. 8, handed down an acquittal at first instance, finding that it had not been proven that the defendant, whilst driving the bus assigned to him, had accelerated towards the complainant, made a move as if to run him over, and caused the complainant to step aside to avoid being struck. It should be noted that both the complainant and the defendant are employed by the same company and that the events took place within the context of their employment relationship.
The private prosecutor substantiated the appeal on the basis of two grounds. Firstly, it was argued that there had been a violation of fundamental rights – pursuant to Article 24 of the Spanish Constitution – in that the complainant had participated in the proceedings for a minor offence without legal representation. The appellant states that the court did not inform him of the procedural rights he could exercise on his own behalf, nor of the possibility of adjourning the hearing to appoint a lawyer, and that, as a result, he was unable to adequately challenge the opposing version of events or to propose or adduce essential evidence.
In relation to this ground of appeal, having analysed the constitutional doctrine on the right to a defence, the judgment confirms that, although the law permits self-representation in proceedings for minor offences, the Constitutional Court has clarified in its Judgment STC 29/2023 that this possibility does not exempt the court from guaranteeing equality of arms and from intervening where the absence of legal representation may lead to a situation of defencelessness.
The court must therefore examine the specific circumstances of each case, paying particular attention to the complexity of the proceedings, the party’s legal knowledge and background, and whether the opposing party has access to legal assistance from which a situation of procedural inequality might be inferred.
In this case, the Provincial Court of Madrid concluded that there had been no genuine situation of defencelessness due to the lack of legal representation during the trial, thereby confirming that there had been no violation of fundamental rights. This is because the party who was not represented by a lawyer was the complainant and not the defendant – and therefore did not face a possible conviction – the proceedings were not particularly complex, there was a pre-existing labour dispute known to both parties, and the complainant had trade union support and access to legal advice.
As regards the second ground of appeal, the appellant alleges an error in the assessment of the evidence, arguing that the judgment at first instance attached undue weight to the internal investigation carried out by the company and that the court failed to view the security footage – which, as we have already noted, was not evidence submitted by either party.
This issue is particularly significant from the perspective of internal investigations, given that the acquittal was based almost exclusively on an internal investigation carried out by the company itself, which ruled out the allegations made, thereby highlighting the value of an internal investigation as a source of evidence.
In this regard, and bearing in mind that the complainant and the respondent were in an employment relationship, the company for which they both worked launched an investigation into incidents that might constitute workplace harassment, at the request of the complainant, who is now the appellant. Following a review of the footage from the security cameras installed on the company’s premises, the investigation concluded with a disciplinary sanction for reckless driving, ruling out the possibility that there had been an attempt to run someone over.
The appellant argues that the acquittal is based solely on that internal investigation, which disregards the reality of the alleged facts (attempted hit-and-run) but results in a disciplinary sanction; therefore, given that the investigation itself concludes with the imposition of a sanction, it must be ruled out that the internal investigation alone can constitute sufficient evidence to support the acquittal.
He argues that the acquittal is based on an unreasonable assessment of the evidence, adding that the court hearing the case did not view the company’s security camera footage during the trial, an omission which exacerbates the judge’s failure to assess the evidence objectively. In particular, the security camera footage was not played back during the trial, and the assessment of that footage carried out by the internal investigation team was accepted as valid.
At this stage, we must recall the interpretation given by the Provincial Court of Madrid regarding the ground of appeal based on an error in the assessment of the evidence. Thus, citing the Supreme Court (Judgment 136/2022 of 17 February 2022), it establishes that the court of second instance cannot reconstruct the proven facts on the basis of a new assessment of the evidence adduced at first instance, that is to say, the appellant may only seek the quashing of the acquittal by challenging the legal basis of the decision on the basis of the facts found to be proven. In other words, an error in the assessment of the evidence will be found where structural defects in the reasoning or structure are identified, and the appeal court may only verify the validity and rationality of the reasoning followed at first instance.
In analysing this specific case, the Provincial Court considers that the appellant puts forward an alternative interpretation of the evidence and that, in the absence of other evidence, the animosity between the parties involved and the subjective nature of the complainant’s assessments were decisive in handing down an acquittal, taking into account the principle of the presumption of innocence.
The judgment concludes by dismissing the second ground of the appeal on the grounds that the internal investigation and its outcome were not interpreted unreasonably, insofar as the investigation did not establish the existence of a threat, but merely reckless conduct from an employment and disciplinary perspective.
The judgment in question is particularly relevant in the context of internal investigations, as it provides an interesting example of the growing role of internal investigations in legal proceedings, offering a balanced perspective on their role as a source of evidence.
Consequently, in this case, the Madrid Provincial Court does not attach decisive weight to the internal investigation, thereby avoiding the risk of automatically carrying over the conclusions reached in the disciplinary proceedings to the judicial proceedings.
However, it appears to suggest that the proceedings might be declared null and void with retroactive effect to the time prior to the oral hearing, for the purpose of examining the evidence – the playback of the security camera recordings – which the court should have ordered. Ultimately, the Provincial Court does not rule that the proceedings are null and void, as the appellant has not raised this issue.
This leaves open the possibility of a judgement of nullity where the findings of the internal investigation are automatically incorporated, without the evidence being examined during the oral hearing.
In light of all this, the ruling confirms that internal investigations are a source of information obtained in the private sphere which may subsequently be incorporated into criminal proceedings, but whose effectiveness will always depend on their compliance with the procedural safeguards applicable to such proceedings. It therefore recognises their usefulness as a contextual element and a source of information, but refuses to attribute to them an independent probative value capable, on its own, of undermining the presumption of innocence.