Evidence Acquisition in Iranian Criminal Law and Its Relationship with the Fundamental Principles of Fair Trial

Abstract

Evidence plays a crucial role in both civil and criminal proceedings. In fact, the function of evidence leads to the discovery of truth and reality, which may have individual and social implications. Evidence constitutes the means of proof in judicial proceedings. The present study is based on a descriptive–analytical method and documentary research using up-to-date library and internet sources. In the Iranian legal system, evidence acquisition is regarded as one of the fundamental pillars of the criminal process, and its role in the realization of criminal justice and the establishment of criminal liability is undeniable. In Iranian law, evidence acquisition is not merely a procedural or formal act; rather, it constitutes an independent legal institution and instrument which, through adherence to legal, Islamic jurisprudential, and human rights principles, guarantees the validity and legitimacy of judicial proceedings and serves as the basis for judicial decision-making in criminal cases. Within this framework, evidence acquisition is examined from both substantive and procedural perspectives. From a substantive standpoint, evidence acquisition concerns the quality, accuracy, and evidentiary value of proof and ensures that the collected evidence is precise, reliable, and effective in uncovering the truth. This substantive dimension demonstrates that evidence acquisition extends beyond a purely physical or formal procedure and requires the analysis, evaluation, and validation of evidence in pursuit of the factual realities of the crime. On the other hand, the procedural dimension of evidence acquisition relates to compliance with legal formalities and rules of criminal procedure, timing requirements, territorial jurisdiction, and the protection of the rights of the parties to the proceedings. Strict observance of this procedural aspect prevents the acquisition of unlawful evidence, the exertion of undue pressure on the accused, and violations of defense rights, thereby ensuring the legitimacy of the judicial process. This distinction between the substantive and procedural dimensions enables a more comprehensive analysis of the evidence acquisition process and facilitates the assessment of its strengths and weaknesses in achieving criminal justice.