Why did the case get called when it arrived at the procuratorate's law firm?

Because the procuratorate accepted it, it does not mean that it will be successful, and lawyers need to intervene.

The case transfer for examination refers to that the public security organ transfers the case file materials and evidence to the people's procuratorate at the same level for examination and decision at the end of the investigation. The public security organ has no way to directly file a lawsuit against the case, and the people's procuratorate decides whether to file a lawsuit after examining the criminal case prosecuted. The transfer of a case for examination and prosecution is one of the necessary processes for public prosecution cases.