This document contains the judgement from the Supreme Court of India in the case of Mukesh Singh vs State (Narcotic Branch of Delhi), dated 31 August 2020. It addresses a crucial legal question regarding whether a trial is vitiated if the investigating officer is also the complainant. The judgement examines various precedents and legal principles, particularly concerning the Narcotic Drugs and Psychotropic Substances (NDPS) Act, to determine if such a scenario inherently leads to bias and entitles the accused to acquittal. This judgement is essential for legal professionals, law students, and anyone interested in criminal jurisprudence and fair trial rights in India.