Investigator’s covert-nature procedural activitiesMarina Sergeevna Kolosovich, Lyudmila Vladimirovna Popova, Anna Fedorovna Zotova, Maria Mikhailovna Bondar and Olga Sergeevna ShamshinaSHS Web Conf., 108 (2021) 04011DOI: https://doi.org/10.1051/shsconf/202110804011