The Right to Fair and Effective Investigation in Pre-trial stage refers to various aspects of criminal procedure designed to safeguard the innocent from the harassment of the state authorities, both judiciary and executive. Each and every accused person of the offence should be treated as an innocent person till the guilt is proved by the court. The accused person has rights to be just, fair, reasonable, and effective before the court in which the court and authorities must apply the just, reasonable and fair procedures on conducting their investigative task. They must perform their duties in accordance with procedure established by law. The United Nations contributed a lot in adopting declarations, conventions, and principles etc. which ensure the rights to fair trial in the court of law of the accused person. However pre-trial investigation is closely connected with fair trial of an accused. Impartial investigation is depending on the authority conducting the investigation. In absence of a separate investigating agency in Bangladesh, the investigating officers who belong to the police force are at times lagging behind the professionalism in wrapping up investigation of crimes for a plethora of reasons. In many instances the investigating officers are alleged to be discharging their duties in a casual manner. Though separate judicial magistracy started its journey about twelve years ago, delayed, defective and biased investigation of crimes is one of the major stumbling blocks that haunt our crippling criminal justice system. Colonial rules, too much reliance on confession of the accused rather than evidence oriented way of investigation and heavy workloads of law enforcing agency are major causes for lackadaisical investigation. Many officers also tend to be conveniently indifferent to the modern trends and technical developments of investigation techniques and human rights of the accused. It is also critical that the investigating officers are well-versed with the essential ingredients of the offences they are investigating. The investigators are also often handicapped in undertaking effective investigation for want of modern gadgets and equipment etc. In this age, the crime detecting members can also in no way sideline the core human dignity of the accused.