The following rule is axiomatic: «in the course of investigative actions, violation of the rule of law is unacceptable.» Compliance of procedural procedures with this principle is an imperative condition of criminal proceedings. Legality determines the order of investigative actions. Legality and order set the standard procedural form of obtaining evidence that in the adversarial and investigative types of the process entails differing procedural content. This defines the differences in the rules used to evaluate personal evidence due to the ideological attitudes embedded in the construction of the law.In Soviet law, the form of interrogation was associated with the goal of achieving the truth, which determines the activities of almost all participants in the proceedings. Consequently, undifferentiated actions of the main participants in court proceedings were acceptable to achieve the truth, and the evidence obtained was admissable. The aim of the investigator’s pursuit of the truth assumed that it was permissible for him to use questions of accusatory etymology when receiving the testimony of a suspect. The adversarial principle is implemented in modern law. In this case, the legal order is formed by two parties with the defense initiating questions to the suspect, which is an element of the proper form of obtaining the testimony of the suspect used in their assessment. The formation of evidence is completed by their examination according to the criterion of admissibility in court proceedings. Until the moment of rebuttal of the presumption of innocence, all evidence presented by the prosecution is inadmissible. By proving guilt, the prosecutor proves the quality of the evidence presented by the prosecution. Thus, the quality of admissibility of evidence is acquired simultaneously with the entry into force of the presumption of the validity of the verdict.