citizen's arrest
Legal term for an arrest made by a private individual, not a law enforcement officer. Often discussed in the context of its legal limits and risks.
In Japan, citizen's arrest is permitted by law, but there is also a risk of false arrest.
逮捕 is a general term for arrest, usually by police. 私人逮捕 specifies that the arrest is made by a private citizen.
Compound of 私人 (private individual) and 逮捕 (arrest).