In the criminal proceedings with regard to serious and especially serious crimes, covert investigative (detective) actions (hereinafter – CIDA) play a crucial part of the efficient means of proving in the criminal procedure through which more than 85 % of such crimes are investigated and solved. A successful outcome of CIDA is only possible subject to the efficient cooperation of investigative and operational officers of the authorized units of competent law enforcement agencies. However, in the law application activities, the interaction of these subjects of the criminal process gives rise to a range of challenging issues making a study of their interaction relevant today. The purpose of this study is to identify the challenging legal and organizational issues inherent in the interaction of investigative and operational officers of the authorized operational units during CIDA, and to substantiate the proposals aimed at finding a solution thereof. The article demonstrates that interaction of an investigative and an operational officer of the authorized operational units should be understood as a necessary activity area of the subjects characterized by administrative independence, which is underlain by law and departmental regulations and coordinated by intermediate objectives, and which is directed by an investigator or a prosecutor by comprehensively combining and efficiently exercising the powers, methods and forms possessed by each of them. The author proves that an investigator’s direct involvement in CIDA is an efficient form of interaction of investigative and operational officers of the authorized units of competent law enforcement agencies. The article offers arguments to prove that an investigator’s order on making CIDA should be submitted particularly to the operational unit of law enforcement agencies which directly makes the CIDA concerned. Given the analysis of the CIDA practice and the CIDA results use as proof in the criminal procedure, it is argued that the protocol on the conduct of a relevant CIDA should be made either by an authorized officer of the operational unit or by an investigator who conducted or participated in the conduct of CIDA. The said protocol should comply with the general rules of recording applicable to the criminal proceedings. The author comes to the conclusion that an appropriate interaction of an investigative and an operational officer of the relevant authorized operational units, the latter being the subjects of law enforcement agencies independent of each other in terms of administrative subordination, which is directed by an investigator or a prosecutor by comprehensively combining and efficiently exercising the powers, methods and forms possessed by each of them, is crucial for increasing the efficiency of CIDA and the use of CIDA results as proof in the criminal procedure, at the same time generally contributing to the successful implementation of the tasks of the criminal process.

Legislation 
1. Instruktsiia z orhanizatsii vzaiemodii orhaniv dosudovoho rozsliduvannia z inshymy orhanamy ta pidrozdilamy Natsionalnoi politsii Ukrainy v zapobihanni kryminalnym pravoporushenniam, yikh vyiavlenni ta rozsliduvanni [Instruction on the organization of interaction of pre-trial investigation bodies with other bodies and units of the National Police of Ukraine in the prevention of criminal offenses, their detection and investigation]: Nakaz Ministerstva Vnutrishnikh sprav Ukrainy [Order of the Interior Ministry of Ukraine] vid 07.07.2017 r. № 575. URL: http://zakon0.rada.gov.ua/laws/ show/z0937-17 (accessed 28.09.2018) (in Ukrainian). 
2. Instruktsiia рro orhanizatsiiu provedennia nehlasnykh slidchykh (rozshukovykh) dii ta vykorystannia yikh rezultativ u kryminalnomu provadzhenni [Guidance for Organization of Covert Investigative (Detective) Actions and Use of the Results Thereof in Criminal Proceedings]: nakaz Heneralnoi Prokuratury Ukrainy, Ministerstva Vnutrishnikh sprav Ukrainy, Sluzhby Bezpeky Ukrainy, Administratsii Derzhavnoi prykordonnoi sluzhby Ukrainy, Ministerstva finansiv Ukrainy, Ministerstva yustytsii Ukrainy [Order of the Prosecutor General of Ukraine, the Interior Ministry of Ukraine, the Security Service of Ukraine, the Ministry of Finance of Ukraine, the Administration of the State Border Service of Ukraine and the Ministry of Justice of Ukraine] vid 16 lystopada 2012 r. № 114/1042/516/1199/936/1687/5. URL: http://zakon4.rada.gov. ua/laws/show/v0114900-12 (accessed 28.09.2018) (in Ukrainian). 
3. Kryminalnyi kodeks Ukrainy [The Criminal Code of Ukraine]: Zakon Ukrainy [the Law of Ukraine] vid 05 kvitnia 2001 r. № 2341-ІІІ. URL: http://zakon.rada.gov.ua/laws/ show/2341-14 (accessed 28.09.2018). 
4. Kryminalnyi protsesualnyi kodeks Ukrainy [Criminal Procedural Code of Ukraine]: Zakon Ukrainy [the Law of Ukraine] vid 13 kvitnia 2012 r. № 4651-VI. URL: http:// zakon2.rada.gov.ua/laws/show/4651-17 (accessed 28.09.2018) (in Ukrainian). 
5. Pro doderzhannia prav liudyny pid chas provedennia operatyvno-tekhnichnykh zakhodiv [On observance of human rights during operational and technical measures]: Ukaz Prezydenta Ukrainy [Decree of the President of Ukraine] vid 07.11.2005 
r. № 1556/2005. URL: http://zakon4.rada.gov.ua/laws/show/1556/2005 (accessed 
28.09.2018) (in Ukrainian). 
6. Pro operatyvno-rozshukovu diialnist [On the Operational and Investigative Activities]: Zakon Ukrainy [the Law of Ukraine] vid 18 liutoho 1992 r. № 2135-ХІІ. URL: http://zakon.rada.gov.ua/laws/show/2135-12 (accessed 28.09.2018). 
7. Pro zabezpechennia bezpeky osib, yaki berut uchast u kryminalnomu sudochynstvi [On ensuring the safety of persons involved in criminal proceedings]: Zakon Ukrainy [the Law of Ukraine] vid 23.12.1993 r. № 3782-XII. URL: http://zakon.rada.gov.ua/ laws/show/3782-12 (accessed 28.09.2018) (in Ukrainian). 
 

Bibliography 
 

Authored books 
8. Bagriy M, Lutsuk V. Protsesualni aspekty nehlasnoho otrymannia informatsii: vitchyznianyi ta zarubizhnyi dosvid [Procedural aspects of secret information, domestic and foreign experience] (Kharkiv, Pravo 2017) 376 (in Ukrainian). 
9. Pohoretskyi M, Funktsionalne pryznachennia operatyvno-rozshukovoi diialnosti u kryminalnomu protsesi [Functional Purpose of Operative-Investigative Activity in the Criminal Process] (Arsis, LTD 2007) 576 (in Ukranian). 
10. Pohoretskyi M, Kryminalno-protsesualni pravovidnosyny: struktura i systema: [Criminal-procedural legal relations: structure and system] (Kharkiv, Arsis LTD, 2002) 160 (in Ukranian). 

Articles 
11. Pohoretskyi M, ‘Nehlasni slidchi (rozshukovi) dii: problemy provadzhennia ta vykorystannia rezultativ u dokazuvanni’ [‘Covert investigative (search) actions, proceedings and usage problems in proving results’] (2013) 1 Yurydychnyi chasopys Natsionalnoi akademii vnutrishnikh sprav 270-77 (in Ukranian). 
12. Pohoretskyi M, ‘Vprovadzhennia instytutu nehlasnykh (rozshukovykh) slidchykh dii v pravozastosovnu praktyku’ [‘Implementation covert institute (search) investigation to law enforcement’] (2012) 2 (28) Borotba z orhanizovanoiu zlochynnistiu i koruptsiieiu (teoriia i praktyka) 56-63 (in Ukranian). 
13. Pohoretskyi M, ‘Zastosuvannia provokatsii v khodi nehlasnykh rozsliduvan: pytannia pravomirnosti’ [‘The use of provocations during secret investigations: the issue of legality’] (2016) 1 Вісник кримінального судочинства 33-43 (in Ukrainian). 
14. Pohoretskyi M, Hotenets V, ‘Protsesualni i orhanizatsiini formy vzaiemodii orhaniv diznannia i dosudovoho slidstva’ [‘Procedural and organizational forms of interaction between the bodies of inquiry and pre-trial investigation’] (2002) 1 Pravo i bezpeka 178- 183 (in Ukrainian). 
15. Pohoretskyi M, Serhieieva D, ‘Nehlasni slidchi (rozshukovi) dii ta operatyvno-rozshukovi zakhody: poniattia, sutnist i spivvidnoshennia’ [‘Covert investigative (search) actions and operational-search measures: concept, essence and value’] (2014) 2 (33) Borotba z orhanizovanoiu zlochynnistiu i koruptsiieiu (teoriia i praktyka) 137-141 (in Ukrainian). 
16. Serhieieva D, ‘Shchodo vyznachennia bezposerednoho subiekta provedennia nehlasnykh slidchykh (rozshukovykh) dii’ [‘Concerning the determination of the direct subject of conducting secret investigators (search) actions’] (2014) 2 Ch 2 Naukovyi visnyk Natsionalnoi akademii vnutrishnikh sprav 34-42 (in Ukrainian). 
17. Spilnyk S, Komarnytska O, ‘Slidchyi yak sub’iekt provedennia nehlasnykh slidchykh (rozshukovykh) dii: za i proty’ [‘The investigator as the subject of conducting covert investigative (detective) actions: for and against’] (2015) 1 (38) Sudova apeliatsiia 21. 
18. Starenkyi O, Tsutskiridze M, ‘Vykorystannia nehlasnykh slidchykh (rozshukovykh) dii yak zasobiv dokazuvannia v kryminalnomu provadzhenni na dosudovomu rozsliduvanni’ [‘Using of covert investigative (search) actions as means of proof in criminal proceedings at pre-trial investigation’] (2015) 1 Pravo Ukrainy 152-161 (in Ukrainian). 

Conference papers 
19. Groshevuy Ju, ‘Do pytannia pro mozhlyvist provedennia nehlasnykh slidchykh dii u kryminalnomu protsesi Ukrainy’ Teoretychni osnovy zabezpechennia yakosti kryminalnoho zakonodavstva ta pravozastosovchoi diialnosti u sferi borotby zi zlochynnistiu v Ukraini: materialy naukovoi konferentsii [‘The question of the possibility of conducting secret investigative actions in the criminal process of Ukraine’ Theoretical bases for ensuring the quality of criminal legislation and enforcement activities in the field of combating crime in Ukraine: materials of the scientific conference] (Pravo 2009) 29-33 (in Ukrainian).