If a single person start performing all the functions of the criminal justice system then it becomes impossible to give justice to the victims because of the following points:

(a) Every function requires special skill to perform the task and if only one person performs all the functions then there is least possibility of cross-checking the solution of the problem.

(b) There is a systematic way to give justice.

e.g.: The police receive a complaint, the defense lawyer tries to define the accused, the judge gives decision in the court and decides the punishment for the culprit.

If only one person performed all these functions of the criminal justice system then it will lead to end of the democratic system.