Legal basis: Provisions on Procedures of Public Security Organs Handling Criminal Cases
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 365 The scope of criminal judicial assistance and police cooperation of public security organs mainly includes the exchange and cooperation of criminal intelligence information, investigation and evidence collection, the delivery of criminal litigation documents, the transfer of evidence materials such as physical evidence, documentary evidence, audio-visual materials or electronic data, the extradition, arrest and expulsion of criminal suspects, defendants or criminals, and other matters of criminal judicial assistance and police cooperation as stipulated in international treaties and agreements.