§ 4
Misprision of felony
Official text prohibited actmental stateif conditionpenaltylegal term
Whoever, having knowledge of the actual commission of a cognizable by a court of the United States, conceals and does not as soon as possible make known the same to some judge or other person in civil or military authority under the United States, shall be or imprisoned not more than three years, or both.
History: (June 25, 1948, ch. 645, 62 Stat. 684 (PDF, 39 MB); Pub. L. 103–322, title XXXIII, §330016(1)(G), Sept. 13, 1994, 108 Stat. 2147 (PDF, 52 MB).)
Simplified explanation
It is a federal crime to know that someone actually committed a federal felony (a serious crime), hide it, and fail to report it as soon as possible to a judge or other civil or military authority.