Investigation play vital role in fair trail/justice that's why legislature impose crucial task on investigating officer/agency. The main purpose of investigation is collection of evidence because court pronounce decision only basis of evidence . Therefore investigation is essential element of justice. Police is a main authority to make/conduct the investigation. Legislature also give wider power to investigating officer/agency to make investigation... police is expert to make investigation because govt. not provide special training to make investigation that's why police is often do mistake in process of investigation. If police collects weak evidence against accused, there may be chance accused free from allegation/charges. If police is not make investigation in proper manner then there may be a chance innocent person may receive punishment/sentence who never committed that offence..   the concept of fair justice may be convert into  unfair justice.........                                               Â
