This is generally a good thing. As the public prosecution agency in criminal cases, after receiving the prosecution opinions and evidence materials from the public security organs, the Procuratorate should conduct a comprehensive review of the evidence materials and believe that there may be a violation of the Criminal Procedure Law. Article 176 of Article 176: Where evidence is collected illegally, the person may be required to explain the legality of the evidence collection. After a comprehensive review of the evidence and materials in the case, the procuratorate deems that the evidence is insufficient, or there are omitted crimes, or that the police violated the law during the investigation. The procuratorate may return the case to the public security agency in accordance with the law and require the public security agency to conduct supplementary investigation.

When reviewing a case, the People's Procuratorate may require the public security organs to provide evidence materials necessary for court trials. The People's Procuratorate reviews the case and if it requires supplementary investigation, it can return it to the public security organ for supplementary investigation, or it can conduct its own investigation. For cases subject to supplementary investigation, the supplementary investigation shall be completed within one month. Supplementary investigation is limited to two times. After the supplementary investigation is completed and transferred to the People's Procuratorate, the People's Procuratorate will recalculate the time limit for review and prosecution. For cases under supplementary investigation, if the People's Procuratorate still believes that the evidence is insufficient and does not meet the conditions for prosecution, it may decide not to prosecute.