In Criminal Justice System (CJS), investigation is alpha and omega of police department. After the lodging of FIR by the police, the CJS starts its work. After lodging of FIR, the prime job of police is to conduct investigation. After investigation, report is prepared u/s 173 Cr.P.C and submitted before the Courts for the decision of cases through prosecutor concerned as described in the section 9 of The Punjab Criminal Prosecution Service (Constitution, Functions & Powers) Act, 2006. Although the result of investigation is not ipsi dixit on the Courts but Courts do consider it while providing justice to the victims, their families and the offenders too. Most of the cases fail in Courts due to defective investigation and Apex Courts of Pakistan have commented a lot regarding the poor quality of investigation. This research study will encompass the 1. Lacunae in police investigation, 2-Reasons for weak conviction, 3- Comparative study of a developed country of choice and developing country of South Asia, 4 -issues, 5- challenges faced during the course of investigation, and 6- way forward to overcome deficiencies. Investigation is the baseline of Police Job. The foremost duty of the Police Agency is to maintain law and order situation and then safety of life and property of the public. The methodology used is qualitative cum quantitative. Books & data were reviewed, interviews of fellow colleagues of different ranks were conducted, views were also ascertained by presenting a questionnaire, and of general public too. Whatever the shape of the lacunas is in the investigations, it brings bad name to the department as culprits are acquitted. It is creating resentment among the society and shaking confidence of citizenry, due to which, the public usually hesitate to approach police for recourse. This situation will lead to self-revenge resulting in anarchy in the society. This is not mere a hypothetical statement but based on actual scenarios happened in the Court Rooms in Punjab. This is a share of my contribution to the cause of public services and to uphold the rule of law in the society with a slogan that no wrong doer should be left unpunished. Not only being a Police Officer but as a common man, I believe provision of justice, the rule of law to be the basic inheritance of man on this earth enshrined in the Constitution of the Islamic Republic of Pakistan, 1973 and in other laws prevalent in Pakistan. The paper is the end product of my own efforts, research and writing, its contents are not plagiarized. The paper reflects my own views based on a literature review, a questionnaire fulfilled by colleague officers, and data collected from different sources. This paper is submitted to the Faculty Police Training College, Sihala, in partial fulfillment of the requirements of the 12th Junior Command Course. The philosophy in the paper is “Nothing matters but the facts. Without them, the science of criminal investigation is nothing more than a guess