Legal basis: Article 108 of the Criminal Procedure Law of People's Republic of China (PRC): (1) Investigation refers to the work of compulsory measures taken by public security organs and people's procuratorates in accordance with the law in order to collect evidence and find out the facts of criminal cases; (2) "Parties" refer to victims, private prosecutors, criminal suspects, defendants, plaintiffs and defendants in incidental civil actions; (3) "Legal representative" refers to the parents, adoptive parents and guardians of the client and the representatives of the organs and organizations responsible for protection; (4) "Participants in litigation" refers to the parties, legal representatives, agents ad litem, defenders, witnesses, expert witnesses and translators; "Agent ad litem" refers to the victim of a public prosecution case and his legal representative or near relative, the person entrusted by the private prosecutor and his legal representative in a private prosecution case to participate in the litigation on his behalf, and the person entrusted by the party involved in an incidental civil litigation and his legal representative to participate in the litigation on his behalf; (6) "Close relatives" refer to husbands, wives, fathers, mothers, sons, daughters, brothers and sisters.