Whoever, being an officer, agent, or employee of the United States, knowingly aids or abets any person engaged in any violation of any of the provisions of law prohibiting importing, advertising, dealing in, exhibiting, or sending or receiving by mail obscene or indecent publications or representations, or books, pamphlets, papers, writings, advertisements, circulars, prints, pictures, or drawings containing any matter advocating or urging treason or insurrection against the United States or forcible resistance to any law of the United States, or containing any threat to take the life of or inflict bodily harm upon any person in the United States, or means for procuring abortion, or other articles of indecent or immoral use or tendency, shall be fined under this title or imprisoned not more than ten years, or both.