Legal analysis: have the right to investigate and collect evidence, and can consult the relevant materials of this case. Agent ad litem: refers to a person who acts as an agent in the name of one of the parties within the scope prescribed by law or authorized by the parties. Without the authorization of the client, the litigation activities carried out by the agent ad litem instead of the client have no legal effect.
Legal basis: Article 38 of the Criminal Procedure Law of People's Republic of China (PRC), defense lawyers can provide legal assistance to criminal suspects 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.