noun
accessory after the fact
Legal term for a person who assists a criminal after the crime has been committed, such as by hiding the offender or destroying evidence.
彼は事後従犯として逮捕された。
He was arrested as an accessory after the fact.
共犯 is a broader term for complicity, including both before and after the crime, while 事後従犯 specifically refers to assistance given after the crime.
Compound of 事後 (after the fact) and 従犯 (accessory). The exact historical derivation is uncertain; the term is used in modern legal contexts.