legal basis: article 18 of the criminal procedure law of the people's Republic of China:
(1) "investigation" refers to the work of public security organs and people's procuratorates in handling criminal cases, collecting evidence according to law, and finding out the case and relevant compulsory measures
(2) "parties" refer to victims, private prosecutors and criminal suspects.
(iii) "legal representative" means the principal's parents, adoptive parents, guardians and representatives of organs and organizations responsible for protection;
(iv) "participants in litigation" means parties, legal representatives, agents ad litem, defenders, witnesses, expert witnesses and translators;
(5) "agent ad litem" refers to the victims and their legal representatives or close relatives entrusted to participate in litigation in public prosecution cases, the private prosecutors and their legal representatives entrusted to participate in litigation in private prosecution cases, and the parties involved in incidental civil litigation and their legal representatives entrusted to participate in litigation;
(6) "Close relatives" refer to husbands, wives, fathers, mothers, sons, daughters, brothers and sisters.