In this study, we propose to address the different issues we have identified from a double perspective: the first part is devoted to the examination of generalities on the international criminal system, its functioning in a normative framework, by touching on the actors who intervene in the investigation procedure, the concepts generally accepted in the international legal system. Particular emphasis is placed on the question of the balance of powers and/or rights of the actors in the trial, the Prosecutor, the judges, the witnesses, the victims and the accused. The second part is devoted to the procedural problems posed by anonymous testimony and to the acts performed in the framework of the investigation procedure by anonymous testimony in a few cases considered more important from the jurisprudential point of view. Particular emphasis is placed on the problems posed by anonymous testimony, the abuse of procedure and, by way of proposing solutions to the problems, a perspective of iure condendo closes our study before giving a conclusion.