CHECKS AND BALANCES IN CRIMINAL INVESTIGATION PROCESS : A COMPARATIVE APPROACH AND REFORM PROPOSALS

Abstract

This research article aims to examine the mechanisms of checks and balances in the criminal investigation process conducted by inquiry officials under the rule of law, focusing on the protection of individual rights and liberties. The study is structured around three primary objectives 1.To study the concepts and legal theories related to the checks and balances of police powers during criminal investigations, particularly in accordance with the rule of law 2.To analyze the mechanisms for external oversight and control over police investigations in foreign legal systems, both in civil law and common law jurisdictions 3.To compare the strengths and weaknesses of investigative oversight mechanisms in Thailand with those in selected foreign countries, and to propose suitable reform guidelines for the Thai legal context.

         This study adopts a qualitative research methodology, primarily through documentary research. It gathers data from statutes, legal doctrines, academic articles, research reports, and relevant foreign legislation. The analysis employs content analysis and comparative legal analysis to evaluate the structure, powers, and oversight mechanisms involved in criminal investigations.

         The findings indicate that: 1.Effective checks and balances in the investigative stage are essential to upholding the rule of law; however, such mechanisms remain vague and underdeveloped in Thai law, thereby undermining the transparency and credibility of the justice process. 2.Countries such as the United States, the United Kingdom, Germany, and France have established comprehensive oversight structures—prosecutors, courts, and independent bodies play critical roles in supervising police investigations from the outset. 3.Thailand's current system centralizes investigative authority under the police and lacks robust external oversight. Therefore, legal and structural reforms are necessary. These include empowering public prosecutors to co-direct investigations, enhancing judicial oversight, establishing independent oversight agencies, and applying modern technology to promote transparency and accountability in the investigative process.