legal ground
1. According to Article 39 of the Criminal Procedure Law, defense lawyers can meet and correspond with criminal suspects and defendants in custody.
2. According to the provisions of Article 40 of the Criminal Procedure Law, defense lawyers can consult, extract and copy the case file from the date when the people's procuratorate examines and prosecutes the case. Other defenders may also consult, extract and copy the above materials with the permission of the people's court or the people's procuratorate.
3. According to the provisions of Article 41 of the Criminal Procedure Law, defenders have the right to apply to the People's Procuratorate and the People's Court for retrieval if they believe that the evidence materials collected by the public security organs and the People's Procuratorate to prove the innocence or light crimes of the criminal suspect or defendant have not been submitted.
4. According to 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 this case from them, or apply to the people's procuratorate or the people's court for collecting and obtaining evidence, or apply to the people's court for notifying 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.