18 U.S.C. § 792 makes it a crime to harbor or conceal someone if you know, or suspect they have committed, or are planning to commit, espionage or related offenses against the U.S. This applies specifically to those who violate sections 793 and 794 of Title 18, which deal with gathering or sharing classified information or defense information with foreign governments. The penalty for this crime is a fine, up to ten years in prison, or both.
18 U.S.C. § 792
Whoever harbors or conceals any person who he knows, or has reasonable grounds to believe or suspect, has committed, or is about to commit, an offense under sections 793 or 794 of this title, shall be fined under this title or imprisoned not more than ten years, or both.
(June 25, 1948, ch. 645, 62 Stat. 736; Pub. L. 103–322, title XXXIII, § 330016(1)(L), Sept. 13, 1994, 108 Stat. 2147.)
