TY JOUR TI Peculiarities of Interrogation of the Hidden Participant of Pre-Trial Proceedings in a Criminal Case KW preliminary investigation KW hidden participant in the process KW protected person KW security KW investigator KW interrogation KW tactical decisions KW pseudonym KW confidentiality of information JO Bulletin of the Kazan Law Institute of MIA Russia AU Mishin, A.V. PY 2022 IS 13 PB Kazan law institute Ministry of Internal Affairs Russian Federation