Mo. Rev. Stat. § 144.675: Penalty assessed for fraud or evasion, notice.

If fraud or evasion on the part of a person is discovered by the director of revenue, he shall determine the amount of which the state has been defrauded, shall add to the amount so determined a penalty equal to twenty-five percent thereof, and shall assess the same against the person. The director of revenue shall promptly thereafter give to the person written notice of the assessment and penalty, which shall be served personally or by certified mail.