Legal basis:
According to Article 35 of the Criminal Procedure Law, the defender's duty is to provide materials and opinions on whether a criminal suspect or defendant is innocent or light, or to reduce or exempt his criminal responsibility, and to safeguard the litigation rights and other legitimate rights and interests of the criminal suspect or defendant.
Article 36 A defense lawyer may provide legal aid to a criminal suspect during investigation; Acting as an agent for complaints and accusations; Apply for changing compulsory measures; Ask the investigation organ about the crimes and cases suspected by the criminal suspect, and put forward opinions.
Article 37 A defense lawyer may meet and correspond with a criminal suspect or defendant in custody. Other defenders, with the permission of the people's courts and people's procuratorates, may also meet and correspond with criminal suspects and defendants in custody.