noun
accessory before the fact
Legal term for a person who aids or abets a crime before it is committed, as opposed to an accessory after the fact (事後従犯).
See also: 事前従犯
事前従犯人として起訴された。
He was indicted as an accessory before the fact.
事後従犯 refers to an accessory after the fact, i.e., someone who helps a criminal after the crime has been committed.
Compound of 事前 (before the fact) + 従犯 (accessory). The exact historical derivation is uncertain; the term is used in modern legal contexts.