"Misprision of felony" is a crime that occurs when someone knows a felony has been committed but fails to inform the authorities about it. The crime originated in English common law and required that citizens report crimes or face criminal prosecution.
1 : to actively second and encourage (something, such as an activity or plan) abet the commission of a crime. 2 : to assist or support (someone) in the achievement of a purpose The singer was abetted by a skillful accompanist.