False Income Tax Return — Defendant's Knowledge of Falsity is when a person willfully and knowingly files a false income tax return with the intention of avoiding paying taxes. This is a criminal offense and is prosecuted under the United States Code, Title 26, Subtitle F, Chapter 75. Types of False Income Tax Return — Defendant's Knowledge of Falsity include: knowingly filing a false return with the intent to evade taxes, claiming false deductions or credits, inflating income, underreporting income, and omitting sources of income.