The Public Prosecutor as one component of the Criminal Justice System that carries out the prosecution function is one of the functions of the government to enforce the law. In the law enforcement process, the Public Prosecutor performs knowledge production through the mechanism of legal interpretation of an act that is suspected of being an instrumental crime. Thus, the Public Prosecutor has a tendency to ignore all aspects of legal relations that contribute to an act that is suspected of being a criminal act. This instrumentalist work pattern, in the end, gave rise to an undeniable monologue logic (one-way) based on his own knowledge and understanding, ignoring normative and empirical facts. As happened in the District Court Decision Number 02/Pid.SusTpk/2021/PN. Pgp jo Decision of the District Court Number 03/Pid.Sus-Tpk/2021/PN. Pgp, where the Public Prosecutor ignores the principles in the pattern of reasoning and legal arguments. Thus, giving rise to the phenomenon of fallacy (misguided thinking) in the indictment. Therefore, it is necessary to study in depth about "how is the pattern of reasoning and arguments of the Public Prosecutor in constructing the indictment that gives rise to monologue logic as a form of fallacy?" The results of this study indicate that the construction of the Public Prosecutor's thinking based on monologue logic is due to the occurrence of fallacies which can be classified as fallacy ad verecundiam and post hoc ego proper hoc fallacy. Thus, ignoring legal protection for the people targeted by the Public Prosecutor.