From Longman Dictionary of Contemporary Englishcitizen's arrestˌcitizen’s arˈrest noun [countable] SCLwhen a person who is not a police officer catches someone and presents them to the police because they have done something illegal Brown made a citizen’s arrest when a youth attempted to rob an elderly woman.
Examples from the Corpus
citizen's arrest• Joseph Harker How does a citizen's arrest work?• He fought with them, before making a citizen's arrest.made a citizen’s arrest• Palmer made a citizen's arrest after tackling the robber as he tried to get away. 