Mariana da Silva França de Oliveira1
The right to evidence as an expression of the presumption of innocence, adversarial proceedings, and full defense
The Brazilian Code of Criminal Procedure grants the accused the right to request evidentiary measures that he or she deems relevant to the defense, as provided in art. 396 A, at the time of the written response to the accusation, and in art. 402, at the end of the evidentiary hearing2. This prerogative reflects the legislator’s recognition of the centrality of evidence in criminal proceedings and of the need to ensure that the defense has effective means to influence the formation of the judge’s conviction.
The judge’s discretion to deny evidence considered impertinent, irrelevant, or dilatory is not in dispute. However, the exercise of this prerogative has had serious implications in light of the principles of the presumption of innocence, adversarial proceedings, and full defense, especially when the absence of evidence capable of raising reasonable doubt regarding the accusatory thesis, whose production was denied, is later used to justify the conviction of the defendant or the increase of the basic sentence, which constitutes an evident logical contradiction and directly violates the procedural and constitutional guarantees of the accused.
The problem of contradictory decisions
At times, we are faced with court decisions that deny evidentiary measures on the grounds that the loss or the quantification of damage would be irrelevant to the characterization of certain offenses. However, it is later observed that these very elements, presumed loss or extent of damage, deemed irrelevant to justify the refusal of evidence, end up serving as grounds for increasing the basic sentence.
Such a practice distorts the logic of criminal proceedings and affronts the principle of full defense, since the accused is convicted and has his or her sentence increased precisely because of the absence of evidence whose production was denied.
In this context, even though it is acknowledged that the judge, as the recipient of the evidence, has discretion in assessing its relevance, the denial of evidentiary measures must be accompanied by proper, clear, and coherent reasoning, on pain of nullity. The absence of sufficient reasoning, especially when the refusal directly affects the conviction or the determination of the sentence, amounts to a restriction of the right of defense.
It is worth mentioning the prohibition of contradictory conduct, enshrined in civil procedure under the maxim venire contra factum proprium, which applies even to the judicial body, as provided in Statement no. 376 of the Permanent Forum of Civil Proceduralists (FPPC)3.
In this sense, if contradictory conduct is forbidden in civil proceedings, this understanding must be applied with even greater rigor in criminal proceedings, which protect legal interests of an existential nature, such as freedom. It is therefore inadmissible that the adjudicating body adopt incoherent conduct that results in serious consequences for the accused, such as a criminal conviction.
The importance of technical evidence in crimes against the economic and financial order
The problem is exacerbated when technical evidence is at stake, such as accounting or financial expert reports, frequently required in crimes involving allegations of pecuniary loss or economic impact. In such cases, assessing the value of the alleged damage or even the causal link between the position held by the individual and the conduct imputed may be decisive both for the characterization of the offense and for the determination of the criminal sanction. Denying the performance of expert examinations or related measures, yet relying on the presumption of loss and the absence of counter evidence to convict or increase the sentence, subverts due process of law and directly violates the right of defense.
Regarding the relevance of technical evidence, Ada Pellegrini Grinover, Antônio Scarance, and Antônio Magalhães Gomes emphasize4
“Expert evidence currently constitutes, in criminal procedure, one of the most effective means for clarifying the facts. The development of the sciences in general has made it possible to increase the use of technical evidence, both in demonstrating the materiality of the criminal offense, through an examination of the corpus delicti, and in proving other data relevant to ascertaining the truth.”
“The judge’s denial of a request for relevant expert evidence results in a restriction of the right to evidence of the prosecution or the defense (see above, section I of this chapter). Once the sentence has been handed down, if the party who suffered prejudice requests on appeal that it be declared void, insisting on the carrying out of the expert examination, the appellate court, recognizing its relevance, must overturn the decision and order the expert examination to be conducted.”
Thus, it is essential to recognize that denying the production of possible and relevant expert evidence, especially in crimes against the economic and financial order, may constitute a restriction of the right of defense and give rise to the nullity of the judgment.
The right to evidence is not a mere procedural formality, but a structural requirement of adversarial proceedings. Without an effective opportunity to produce evidence, the exercise of the right of defense becomes merely illusory5.
What can therefore be seen is that the denial of evidentiary measures cannot coexist with court decisions that simultaneously rely on the absence of such evidence to support the conviction and justify the increase of the basic sentence. Such a contradiction violates the minimum coherence expected of judicial reasoning and infringes upon the fundamental rights of the accused.
The theory of loss of a probative chance
In light of the above, the application of the so called theory of loss of a probative chance in criminal proceedings deserves emphasis. Originally developed in the field of civil liability, its transposition to criminal procedure in Brazil was driven by Alexandre Morais da Rosa and Fernanda Mambrini Rudolfo6.
Loss of a probative chance occurs when the State, through omission or unjustified refusal, prevents the production of evidence potentially relevant to the exercise of full defense. In these cases, State inaction, either due to the unmotivated rejection of evidentiary measures requested by the defense or the lack of initiative in producing available evidence, limits the accused’s ability to demonstrate his or her innocence or, at the very least, to raise reasonable doubt.
This is not a mere divergence from defensive requests, but a true violation of the constitutional guarantees of due process of law (art. 5, LIV, Federal Constitution), adversarial proceedings and full defense (art. 5, LV, Federal Constitution), and the presumption of innocence (art. 5, LVII, Federal Constitution). This is because the possibility of producing evidence constitutes a right guarantee of the accused, whose observance is indisputable.
It should be noted that the assessment of evidentiary production by the prosecution authorities is often associated with tunnel vision, guided mainly by confirmation bias, that is, the human tendency to value information that confirms initial hypotheses7. Thus, investigators, prosecutors, and judges tend to interpret and produce elements that reinforce a prior idea of guilt, subverting the logic of criminal proceedings, which is or should be structured on the presumption of innocence.
In other words, the granting or denial of the production of certain evidence, as well as the evaluation of the evidence already in the case file, is often conducted in a way that corroborates the initial accusatory theses, while ignoring or discounting elements that point in a different direction.
In this scenario, the theory of loss of a probative chance functions as a real remedy for tunnel vision, since it imposes on criminal prosecution authorities the duty to conduct investigations and proceedings in a way that ensures the material conditions necessary for the full exercise of the right of defense, and not only for confirming the initial accusatory hypothesis.
Given the above, even though the burden of proof lies entirely with the prosecution, when the evidence requested by the defense is possible and reasonable, the courts must ensure its production, under penalty of violating the constitutional rights guaranteed to the accused.
Conclusion
In conclusion, the denial of essential evidence, combined with its indirect use against the defendant, constitutes one of the most serious forms of restriction of the right of defense. It is not enough to recognize that the judge is the recipient of the evidence and therefore has discretion to accept or deny its production, it is necessary to require that any denial be duly reasoned and, above all, that it not be transformed into a procedural trap against the accused. Only then will it be possible to preserve the substance of the presumption of innocence, full defense, and adversarial proceedings, which are indispensable pillars of democratic criminal procedure.
[1] Bachelor of Laws from the Rio de Janeiro State University (UERJ). Lawyer and partner at the law firm Paulo Freitas Ribeiro Advogados Associados. Email address marianafranca@paulofreitasribeiro.adv.br.
[2] BRAZIL. Decree Law no. 3.689, of October 3, 1941. Establishes the Code of Criminal Procedure. Art. 396 A “In the response, the accused may raise preliminary objections and allege everything that is relevant to his or her defense, submit documents and explanations, specify the evidence sought, and list witnesses, giving their particulars and requesting that they be summoned where necessary.” Art. 402 “Once the evidence has been produced, at the end of the hearing, the Public Prosecution Service, the private prosecutor and the assistant to the prosecution, and then the accused, may request any measure whose necessity arises from circumstances or facts established during the evidentiary hearing.” Available at http://www.planalto.gov.br/ccivil_03/decreto lei/del3689.htm. Accessed on Oct. 7, 2025.
[3] Statement no. 376 “The prohibition of contradictory conduct applies to the judicial body.” Approved at the FPPC meeting. Available at https://diarioprocessual.com/wp content/uploads/2020/05/enunciados forum permanente processualistas civis fppc 2020 atualizado.pdf. Accessed on Oct. 15, 2025.
[4] GRINOVER, Ada Pellegrini FERNANDES, Antonio Scarance GOMES FILHO, Antonio Magalhães. As Nulidades no Processo Penal, 10th revised, updated, and expanded edition. São Paulo Editora Revista dos Tribunais, 2007, pp. 174 and 181.
[5] Thus, the right to evidence stands out as a particularly important aspect in the framework of adversarial proceedings, since evidentiary activity represents the central moment of the proceedings, closely linked to the allegation and indication of the facts, it aims to make it possible to demonstrate the truth and is therefore of particular relevance to the content of the judicial decision. The concrete exercise of the right of action and of the right of defense is essentially subordinated to the effective possibility of presenting to the judge the reality of the facts on which the parties’ claims are based, that is, to their ability to make use of the evidence. Brazilian case law is settled in this respect and stresses the need to ensure that both parties have all the means necessary to submit evidentiary material. If this does not occur, case law generally refers to a restriction of the right of defense or of the right of accusation (GRINOVER, Ada Pellegrini FERNANDES, Antonio Scarance GOMES FILHO, Antonio Magalhães. As Nulidades no Processo Penal, 10th revised, updated, and expanded edition. São Paulo Editora Revista dos Tribunais, 2007, pp. 145 and 146).
[6] ROSA, Alexandre Morais da RUDOLFO, Fernanda Mambrini. A teoria da perda de uma chance probatória aplicada ao processo penal, The theory of loss of a probative chance applied to criminal proceedings. Revista Brasileira de Direito, Passo Fundo, RS, Brazil, v. 13, n. 3, pp. 455–471, 2017. DOI 10.18256/2238 0604.2017.v13i3.2095. Available at https //seer.atitus.edu.br/index.php/revistadedireito/article/view/2095. Accessed on Nov. 7, 2025.
[7] FINDLEY, Keith A. Tunnel Vision. In CUTLER, B. (ed.). Conviction of the Innocent Lessons from Psychological Research. Washington, DC APA Press, 2010. (University of Wisconsin Legal Studies Research Paper, no. 1116). Available at https //ssrn.com/abstract=1604658. Accessed on Nov. 7, 2025.