Evidence in lawsuits, especially in criminal lawsuits, has a special place and importance, and gathering evidence means obtaining and creating evidence, which is considered as one of the most important elements of the criminal proceedings process, and without it, the possibility of attributing criminal behavior to the perpetrator or It will not be possible to prove his innocence and, as a result, to carry out the punishment and protective and educational measures or declare his innocence. In criminal matters, reasons are not prepared in advance, but after the criminal event, they should be collected. The most important defense rights of the accused, which should be taken into consideration in order to protect the rights of individuals and their human dignity, in addition to respecting the principle of acquittal, the right to use the assistance of a lawyer, to explain the accusation, to prohibit insinuations and omissions of the accused, the right to have It is the right to remain silent and impartial in the proceedings. In this regard, respect for the defendant's defense rights is related to the concept of protecting the rights of individuals and respecting the human status of human beings, and the violation of these rights harms human dignity and leads to ignoring the rights of individuals, deviating from the principle of legality and legitimacy in the acquisition of evidence, which in the end, makes the evidence obtained by not observing the defense rights of the accused invalid and inadmissible. Therefore, the cited reasons should be valid and studied with legal methods and refrain from resorting to invalid reasons that are studied with illegal methods.