The objective of this research is to conduct a comparative analysis of the criminal justice systems in Pakistan and the UK, focusing on their respective roles and investigative procedures. This study employed doctrinal legal research methods to analyze the legislative frameworks, procedural procedures and institutional structures that regulate investigations in Pakistan and the UK. The Researchers was attributing the significant disparities in the study methodology to cultural, historical and institutional factors. The public widely distrusts Pakistan's criminal justice system, attributing to low conviction rates to institutional inefficiencies, widespread corruption, and insufficient resources that hinder investigations. On the other hand, the UK emphasizes the need to maintain professionalism, transparency, and adherence to due process. A commitment to human rights norms, effective supervision systems, and adequately resourced law enforcement organizations facilitate these purposes. This study thoroughly examines legislation, judicial judgments, and academic publications to uncover the differences in research methodology between the two countries. The findings emphasize the crucial need to conduct thorough inquiries to maintain public trust in the criminal justice system. Pakistan must proactively combat corruption, enhance transparency, and strengthen its institutions to rectify its underlying issues. However, the UK places great importance on the principles of due process and accountability, since they play a crucial role in fostering public trust and confidence in investigations. The results of this comparative research shed insight on the difficulties of conducting investigations in diverse legal environments and emphasize possible opportunities for improvement in both nations.