The Principle of Legal Certainty in the Shadow of Discretion: A Critical Review of the Criminal Investigation Stage

Investigation is a very decisive initial phase in the process of handling a criminal case because it serves to assess whether a legal event can be classified as a criminal offense. This stage requires the application of the principle of legal certainty to ensure that every action taken by law enforcement officials remains within a clear and accountable legal path. In practice, law enforcement officials are given discretionary authority to respond to certain situations that have not been explicitly regulated in written legal norms. This research uses a normative juridical method with an approach to legislation and case study analysis to examine the extent to which the exercise of discretion by law enforcement officials can affect legal certainty at the investigation stage. The results show that Perkapolri Number 6 of 2019 can obscure legal certainty and open opportunities for abuse of authority. In addition to regulatory analysis, this research also analyzes several cases, such as the case of police shooting a drug dealer for trying to injure police officers, corruption in social assistance and the case of KPI employees. The results show that discretion is often used without a clear accountability mechanism and has the potential to violate individual rights. This condition is exacerbated by the absence of time limits and the mixing of process stages. The research concludes that although discretion is needed in certain circumstances, its use must be strictly limited and accountable. Therefore, strengthening internal regulations, consistent implementation of case title, and increasing the function of external supervision such as Kompolnas are needed to maintain the principle of legal certainty in the criminal justice system.