Legal basis:
Procedures for handling criminal cases by public security organs
Article 41 When interrogating a criminal suspect for the first time or taking compulsory measures against him, the public security organ shall inform the criminal suspect that he has the right to entrust a lawyer as a defender, and inform him that if he fails to entrust a defense lawyer due to financial difficulties or other reasons, he may apply for legal aid from a legal aid institution. Information should be recorded.
Article 57 Public security organs must, in accordance with legal procedures, collect all kinds of evidence that can prove the criminal suspect's guilt or innocence and the seriousness of the crime. It is necessary to ensure that all citizens who are related to or know the case have the conditions to provide evidence objectively and fully, and they can be hired to assist in the investigation except in special circumstances.
Article 58 When collecting evidence from relevant units and individuals, public security organs shall inform them that they must provide evidence truthfully.
Evidence involving state secrets, commercial secrets and personal privacy shall be kept confidential.
Whoever forges, conceals or destroys evidence shall be investigated for legal responsibility according to law.
Fifty-ninth public security organs to obtain evidence from the relevant units and individuals, should be approved by the person in charge of the case handling department, issued a notice of evidence collection. The transferred unit or individual shall stamp or sign the notice, and if it refuses to stamp or sign, the public security organ shall indicate it. When necessary, the content of evidence and the process of obtaining evidence shall be fixed by means of audio or video recording.
Article 67 confessions of criminal suspects collected by illegal methods such as extorting confessions by torture, witness testimonies and victim statements collected by illegal methods such as violence and threats shall be excluded.
If the collection of material evidence and documentary evidence violates legal procedures and may seriously affect judicial justice, it shall be corrected or given a reasonable explanation; If it cannot be corrected or a reasonable explanation cannot be given, the evidence shall be excluded.
Evidence that should be excluded in the investigation stage shall be excluded according to law with the approval of the person in charge of the public security organ at or above the county level, and shall not be used as the basis for requesting approval of arrest and transfer for review and prosecution.
If the people's procuratorate thinks that there may be cases of collecting evidence by illegal means and asks the public security organ to explain it, the public security organ shall promptly investigate and explain it in writing to the people's procuratorate.