Object of research: legal relations that arise between the participants of the criminal process at the stage of pre-trial investigation during the conduct of investigative (search) actions, establishing the circumstances of the criminal offense, the guilty of the suspect. Purpose: to solve the scientific problem and to substantiate the theoretical and legal provisions of the Institute of investigative (search) actions, the powers of the prosecution party when applying the mechanism of their conduct, providing guarantees for the procedural fixation of conducting investigative (search) actions on the basis of due legal procedure with the help of a protocol, technical means, prosecutorial supervision in the form of procedural guidance as well as procedural control of an investigating judge in case of a temporary restriction of the rights and freedoms of the participants in the process, and as well as fixing investigators (search) actions using the protocol, the use of technical means. Methods: general and special methods of cognition, in particular: dialectical, formal-logical methods (induction and deduction, analysis and synthesis), systemic-structural, structural-functional, historical-comparative (genetic) method, statistical and sociological methods (surveys and questionnaires , processing of the received data, analysis of empirical information), etc. Theoretical and practical results, scientific novelty: the design of the theoretical and practical provisions of the institute for the conduct of individual investigative (search) actions and the mechanism of their conduct at the stage of pre-trial conduct by the investigator, the prosecutor in the case of a temporary restriction of procedural rights and freedoms of the participants of the process, which are conducted on the basis of the order of the investigator judges; certain theoretical and practical provisions for the conduct of secret investigative (search) actions were determined, the mechanism of their conduct during the collection, research and evaluation of facts, factual data, information about the facts, which are procedurally fixed by means of the procedural form in the protocol as evidence by the investigator, the prosecutor, were provided practical recommendations for the destruction of materials based on the results of secret investigation (search) actions, which have not been confirmed with regard to the suspect; established and provided the theoretical substantiation of the procedural powers of the prosecution party and the investigating judge in case of obtaining a decision on conducting investigatory (search) actions that temporarily restrict the procedural rights, freedoms and interests of the participants in criminal proceedings, types of judicial control over the execution of the decision are proposed; Improved: general provisions for the initiation of pre-trial proceedings in case of receipt of an application, notification of a criminal offense, during investigation (investigatory) actions, practical recommendations for the procedure of pre-trial investigation of criminal offenses and / or criminal misdemeanors, determination of the terms of investigation, inadmissibility of disclosure of information of pre-trial investigation; legal provision of procedural rights of participants in criminal proceedings by means of prosecutorial supervision in the form of procedural guidance during the announcement of suspicion, abolition of unreasonable procedural decisions of the investigator, assignment of conducting investigatory (search) actions; procedural aspects of the procedural independence of the investigator to establish the circumstances of the criminal offense, the decision to close the criminal proceedings and / or to send the criminal proceedings to the court, as well as to ensure judicial protection of the rights, freedoms and legal interests of the person and citizen in the case of appeal of procedural actions (inaction); or decisions in the field of criminal procedural relations. Practical significance: the results obtained can be used in the research area during further scientific development of questions regarding the mechanism of conducting investigation (search) actions in criminal proceedings; in the field of lawmaking during the preparation of drafts, amendments and additions to the current CPC of Ukraine regarding the improvement of the mechanism for carrying out investigative (search) actions in case of proving the circumstances of a criminal offense, determining the guilty of a suspect in a criminal proceeding. Sphere of use: in educational and methodical work during lectures and practical classes with students of higher legal educational institutions on such disciplines as "Criminal Procedure of Ukraine"; "Organization of Judicial and Law Enforcement Bodies"; "Judiciary law"; "Prosecutor's Office of Ukraine"; "Bodies of pre-trial investigation of Ukraine". The obtained results of the study can also be used in the preparati
