Criminal cases refer to cases in which criminal suspects and defendants are accused of violating social relations protected by criminal law, and the state conducts investigation, trial and criminal sanctions in order to investigate the criminal responsibility of criminal suspects and defendants. In criminal cases, the national criminal judicial organs usually take the initiative to intervene. After the victim or the masses report the case, the public security and procuratorial organs will intervene in the investigation. Then the people's procuratorate prosecuted the defendant on behalf of the state, and the court, as a judge of the law, conducted a fair trial to achieve the criminal law purpose of punishing criminals and protecting the people.