Purpose: After the literature reviewed and our reported research we can conclude that the investigation, prevention and detection of criminal offenses, which occur in the Slovenian Armed Forces, certainly represent an area that presents an unavoidable challenge to the Ministry of Defence. We can say that we do not see any reasonable arguments to insist on the dualism of investigation of criminal offenses. Criminal offences that occur in the Slovenian Armed Forces and its missions abroad are, in accordance with regulations, investigated by two bodies: the Military Police and the Criminal Investigation Department of the Intelligence and Security Service. Those two services are differently, have different powers and different areas of jurisdiction. This raises a key question: "Does it make sense to insist on the dualism of Criminal Investigation in the Ministry of Defence/Slovenian Armed Forces?" Design/Methods/Approach: Based on theoretical considerations and empirical discoveries of the problem of Criminal Investigation in the Slovenian Armed Forces, our research was conducted using a focused structured interview. The research involved professionals from the State Prosecutor's Office, judiciary, court, police, military police, police, union, and the advocacies. The research method and target group of interviewees allowed us to test the thesis, while at the same time the study puts forward proposals to resolve the problem. Findings: It is a fact that the Military Police and the Criminal Investigation Department of Intelligence and Security Service require reorganization and changes to adapt to newly created social conditions, in order to increase efficiency, legal certainty, professionalism, economics and operational readiness. Originality/Value: The results clearly indicate unreasonable duplication of functions, ambiguity of powers and the complete absence of systemic thinking, a holistic approach, holistic decision-making, and holistic action. We perceived the problem, defined it and offered some solutions in the field of Criminal Investigation in the Slovenian Armed Forces.