It's especially true with the FBI or any other person connected with the federal government in an investigation. Making false statements is a separate crime in itself. 18 USC § 1001 [1]

[1] http://www.law.cornell.edu/uscode/text/18/1001

[Fascinating article published originally in WSJ] http://ourtaxdollarsatwork.wordpress.com/2012/04/11/federal-...

[How to Avoid Going to Jail under 18 U.S.C. Section 1001 for Lying to Government Agents] http://corporate.findlaw.com/litigation-disputes/how-to-avoi...