Lawyers should keep confidential the relevant information and materials that their clients and others are unwilling to disclose in their practice activities. However, criminal facts and information that endanger national security, public safety and seriously endanger the personal safety of others are excluded.
Article 43 of the Criminal Procedure Law: With the consent of witnesses or other relevant units and individuals, defense lawyers may collect materials related to the case from them, or apply to the people's procuratorate or the people's court to collect and obtain evidence, or apply to the people's court to notify witnesses to testify in court. With the permission of the people's procuratorate or the people's court, and with the consent of the victim or his close relatives or witnesses provided by the victim, the defense lawyer may collect materials related to the case from them.