legal ground
Article 40 of the Criminal Procedure Law
From the date when the people's procuratorate examines and prosecutes the case, the defense lawyer may consult, extract and copy the case file. Other defenders may also consult, extract and copy the above materials with the permission of the people's court or the people's procuratorate.
Article 41
Defenders have the right to apply to the people's procuratorate or the people's court for obtaining the evidence materials collected by the public security organs and the people's procuratorate to prove the innocence or light crimes of the criminal suspects and defendants during the investigation, examination and prosecution.
Article 43
With the consent of witnesses or other relevant units and individuals, defense lawyers may collect materials related to the case from them, 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.