<![CDATA[The use of undercover investigation techniques in combating narcotics crimes has increased in response to the growing complexity of organised crime. However, the Indonesian legal framework governing these techniques remains fragmented across sectoral regulations and is not comprehensively integrated into criminal procedure law, limiting procedural oversight and investigative accountability. This study examines how regulatory fragmentation affects the implementation of the dominus litis principle and proposes a reconstruction model to strengthen procedural supervision. The research uses a prescriptive normative legal method, drawing on statutory, conceptual, comparative, and case approaches. The findings demonstrate that fragmented regulations confine the dominus litis function primarily to prosecutorial control after the investigation stage, preventing effective preventive supervision over investigative legality and evidence acquisition. To address this limitation, the study proposes the Integrated Procedural Supervision Model, which positions public prosecutors as procedural supervisors while preserving investigators' institutional independence. The model is founded on the principles of integrated criminal justice, procedural supervision, accountability, and procedural justice. This study contributes to the development of Indonesian criminal procedure law by reconceptualising the dominus litis principle as a procedural supervisory mechanism and providing normative recommendations for harmonising regulations governing undercover investigation techniques.]]>
