party to the case; parties concerned
Legal term referring to a person directly involved in a case or incident, such as a plaintiff, defendant, or subject of investigation.
Information cannot be disclosed without the consent of the party to the case.
The police are questioning the person concerned in the case.
当事者 is a broader term for any person directly involved in a matter or dispute, while 事件本人 specifically refers to a party in a legal case or incident.
関係者 includes anyone related to an event, not necessarily a direct party; 事件本人 is more narrowly the principal person involved.
Compound of 事件 (case, incident) and 本人 (the person himself/herself). The exact historical derivation is uncertain, but the term is used in modern legal and formal contexts.