After applying to the court for transfer or filing a case, if you inquire in person, you need the court to issue a letter of investigation and evidence collection; If it is necessary for filing a case, it needs to be searched before filing a case. It is recommended to entrust a lawyer to retrieve it. If the defendant is an individual, he can apply to the court to issue a letter of assistance in investigation, and then go to the police station to obtain household registration information. If the defendant is a unit, he can also find a lawyer to obtain business information.
Legal basis: People's Republic of China (PRC) Lawyers Law.
Article 33 A lawyer who acts as a defender has the right to meet a criminal suspect or defendant who is detained or under residential surveillance with a lawyer's practice certificate, a law firm certificate, a power of attorney or a power of attorney for legal aid in accordance with the provisions of the Criminal Procedure Law. Defense lawyers are not monitored when meeting with criminal suspects and defendants.
Article 34 A lawyer who acts as a defender has the right to consult, extract and copy the case file from the date when the people's procuratorate examines and prosecutes the case.
Article 35 An entrusted lawyer may, according to the needs of a case, apply to a people's procuratorate or a people's court to collect and obtain evidence, or apply to a people's court to notify witnesses to testify in court.
If a lawyer investigates and collects evidence by himself, he may, with the lawyer's practice certificate and the certificate of the law firm, investigate the situation related to undertaking legal affairs with the relevant units or individuals.