Section 17 in THE BHARATIYA NYAYA SANHITA, 2023 – BNS

Act done by a person justified, or by mistake of fact believing himself justified, by law.

  1. Nothing is an offence which is done by any person who is justified by law, or who
    by reason of a mistake of fact and not by reason of a mistake of law in good faith, believes
    himself to be justified by law, in doing it.
    Illustration.
    A sees Z commit what appears to A to be a murder. A, in the exercise, to the best of his
    judgment exerted in good faith, of the power which the law gives to all persons of apprehending
    murderers in the fact, seizes Z, in order to bring Z before the proper authorities. A has
    committed no offence, though it may turn out that Z was acting in self-defence.