The existence of the principle of irrevocability of phases is almost uniformly accepted by the doctrine and the law practise, but it is not directly mentioned in the Turkish Criminal Procedure Code or in other relevant laws. Although the principle is not directly included in the legislation, there are various regulations that indirectly indicate its existence. At the beginning of these regulations, comes Article 174 of TCPC. According to this article, an indictment that has not been returned within 15 days of its delivery will be considered accepted. According to Article 175 of TCPC, as soon as the indictment has been accepted, the investigation phase ends and the main trial phase (phase of prosecution) starts. Once the main trial phase starts, there is no return to the phase of investigation. The doctrine and practise generally accept that after passing of these 15 days, the return of the indictment is no longer allowed. Because the passing of these 15 days removes the authority, which has been given to the court, to return the indictment. The same conclusion can be reached from article 267 and following articles of TCPC. Because these articles give the opportunity to reconsider the decision which has been made by the court. But even in those cases, there is no return to the investigation phase. This means indirectly that there is no response from the main trial phase to the investigation phase. Generally accepted, there are two phases in criminal procedure; namely, phase of investigation and the phase of the main trial. Although it is not directly mentioned in the current Turkish Criminal Procedure Code, there is an intermediate trial phase. This phase, which allows the return of the indictment with a limited period of time, is not important for our study because it is still considered as the investigation phase in terms of our current law. Because when the irrevocability of the phases is mentioned, what is meant exclusively is the irreversibility from the main trial phase to the investigation phase. Since the intermediate trial phase is also counted as a part of the investigation phase, we can indirectly say that it is not possible to return from the main trial phase to the intermediate trial phase. Since the legislator does not qualify a separate phase, although there is no obstacle in terms of the principle of irrevocability from phases, it is not clear whether the prosecutor can withdraw the indictment independently of the court during the intermediate trial phase; to put it more accurately, it does not seem possible since it is not foreseen in the legislation. For this reason, although it has no place in the legislation, it is rightly defended in our doctrine that the prosecutor’s office should be given such a withdrawal authority. Indeed, with the start of the main trial phase, the phase in which the prosecutor is the emperor comes to an end, and the task of executing and managing the process passes to the court. Thus, when the main trial phase is initiated, the obligation of the court to perform and terminate the process starts. However, in some cases, the lack of prosecution conditions or the emergence of obstacles to judgement may require returning to the investigation phase or making a decision to stop and correcting the relevant deficiencies by out-of-court authorities. For this reason, in some country practises, it is possible to return to the investigation phase during and/or after the main hearing period. The recent annulment decision of the Constitutional Court regarding the accelerated proceeding also necessitates a return to the investigation phase. This study aims to explain within the framework of comparative law that it should be possible to return to the investigation phase in order to eliminate the injustices (problems in the context of a fair trial) that may arise in these and similar cases.