Legal basis: Criminal Procedure Law of People's Republic of China (PRC).
Article 38 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 115 A public security organ shall investigate a criminal case that has been put on file, and collect and obtain evidence of the criminal suspect's guilt or innocence, whether the crime is minor or serious. An active criminal or a major suspect may be detained in advance according to law, and a criminal suspect who meets the conditions for arrest shall be arrested according to law.
Thirty-sixth legal aid institutions can send lawyers on duty in people's courts, detention centers and other places. If the criminal suspect or defendant does not entrust a defender or the legal aid institution does not entrust a lawyer to defend him, the lawyer on duty will provide legal assistance to the criminal suspect or defendant, such as legal consultation, suggestions on procedure selection, application for changing compulsory measures, and suggestions on handling cases. The people's courts, people's procuratorates and detention centers shall inform the criminal suspects and defendants that they have the right to meet the lawyers on duty, and provide convenience for the criminal suspects and defendants to meet the lawyers on duty.