Abstract: The subject of the study is the acts of prosecutorial response in the supervision of the legality of the preliminary investigation in the form of an inquiry. The purpose of the study is to analyze the measures of the prosecutor's response used by the prosecutor in overseeing the legality of the investigation, the opinions of scientists and practitioners on the issues under consideration and to propose their own ways to solve the identified problems. To achieve this goal, the author of the study analyzes the reasons for the increased attention to the procedural activities of interrogators. The author pays special attention to the acts of prosecutorial response to illegal actions of supervised subjects. In the course of his research, the author uses dialectical, logical, systemic, functional and formal legal methods. As a result of the conducted research, the author comes to the conclusion that the inquiry was introduced by the federal legislator as a simplified form of crime investigation. The requirements for interrogators allow for the appointment of persons who do not have higher legal education, which, together with the general low professional training of employees, is a determinant factor in the admission of violations. Direct managers often do not formally respond to violations committed by the investigator, and therefore the active participation of the supervising prosecutor remains the only guarantor of legality. The supervising prosecutor has a range of acts of prosecutorial response: from mild to more severe, which allows a flexible approach to the choice of ways to respond to violations. The author of the study proposed to consolidate the right of an inquirer to appeal, with the consent of his supervisor, to a higher prosecutor with a complaint about the demands made to him.

Keywords: legality, measure of prosecutorial response, act of prosecutorial response, preliminary investigation, prosecutor's decision, written instruction, prosecutor's demand, interrogator, inquiry, Prosecutor's supervision