Legal basis: Criminal Procedure Law of People's Republic of China (PRC).
Article 37 The duty of a defender is to present materials and opinions on whether a criminal suspect or defendant is innocent, light or relieved of criminal responsibility according to facts and laws, and to safeguard the litigation rights and other legitimate rights and interests of the criminal suspect or defendant.
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.