Lying to the FBI would already be severe, IMO. It's a felony.
Here is an excerpt, more info at link:
Making false statements
From Wikipedia, the free encyclopedia
Making false statements (18 U.S.C. § 1001) is the common name for the United States federal crime laid out in Section 1001 of Title 18 of the United States Code, which generally prohibits knowingly and willfully making false or fraudulent statements, or concealing information, in "any matter within the jurisdiction" of the federal government of the United States, even by mere denial.[1] A number of notable people have been convicted under the section, including Martha Stewart,[2] Rod Blagojevich,[3] Scooter Libby,[4] Bernard Madoff,[5] and Jeffrey Skilling.[6]
This statute is used in many contexts. Most commonly, prosecutors use this statute to reach cover-up crimes such as perjury, false declarations, and obstruction of justice and government fraud cases.[7]
Its earliest progenitor was the False Claims Act of 1863, and in 1934 the requirement of an intent to defraud was eliminated to enforce the National Industrial Recovery Act of 1933 (NIRA) against producers of "hot oil", oil produced in violation of production restrictions established pursuant to the NIRA.
http://en.wikipedia.org/wiki/Making_false_statements