Abstract
<jats:p>The study of problematic aspects related to the transformation of materials obtained during operational and investigative activities into evidence in criminal proceedings is of great relevance. The article highlights the problem of ensuring a balance between the need for effective crime prevention, especially under martial law, and the observance of fundamental human rights and freedoms. The essence and functional purpose of operational and investigative activity are examined as an independent area of law enforcement work, which has its own tasks, principles, and primarily covert tools. The legal nature of operational and investigative materials is analyzed as pre-procedural, orienting information that requires further legalization in accordance with the law in order to acquire the status of evidence. The article substantiates the need for a comprehensive approach to resolving existing conflicts between the Law of Ukraine “On Operational and Investigative Activities” and the Criminal Procedure Code of Ukraine. The methods used in the study include the formal-legal, systemic-structural, comparative-legal analysis, and synthesis. Applying these methods made it possible to deconstruct the regulatory provisions governing the process of proof, reveal their systemic connections, and identify contradictions. Key requirements for evidence, particularly relevance and admissibility, are analyzed in the context of using information obtained in a non-procedural way. Judicial practice regarding the inadmissibility of evidence obtained before the inclusion of information in the Unified Register of Pre-trial Investigations is also examined. The article analyzes the complex and multi-stage process of transforming operational and inves-tigative materials into evidence, where the institution of covert investigative (search) actions plays a key role. The author argues that effective and coordinated interaction between operational officers and investigators at all stages of criminal proceedings is a decisive condition for forming a proper and admissible evidentiary base. The study also examines the impact of the special regime of pre-trial investigation under martial law, particularly the prosecutor’s powers provided for in Article 615 of the Criminal Procedure Code of Ukraine, on the procedure for obtaining authorizations to conduct covert measures. The article concludes that the existing problems indicate an urgent need to improve both legislation and law enforcement practice. Particular attention is given to the concepts of “operational and investigative support of investigation,” “implementation of operational and investigative materials,” and “admissibility of evidence.” The expediency of granting customs authorities the right to carry out operational and investigative activities and restoring the unified system of military justice has been established. The author offers proposals for improving legal regulation in order to adapt it to modern challenges associated with large-scale armed aggression and to ensure a clear mechanism for legalizing the results of operational and investigative activities without violating procedural guarantees. Keywords: operational and investigative activity, evidence, criminal proceedings, transformation of materials, admissibility of evidence, covert investigative (search) actions, martial law, pre-trial investigation, operational and investigative support, criminal analysis.</jats:p>