Mo. Rev. Stat. § 575.050: False affidavit — penalties.

1. A person commits the offense of making a false affidavit if, with purpose to mislead any person, he or she, in any affidavit, swears falsely to a fact which is material to the purpose for which said affidavit is made.

2. The provisions of subsections 2 and 3 of section 575.040 shall apply to prosecutions under subsection 1 of this section.

3. It is a defense to a prosecution under subsection 1 of this section that the person retracted the false statement by affidavit or testimony but this defense shall not apply if the retraction was made after:

(1) The falsity of the statement was exposed; or

(2) Any person took substantial action in reliance on the statement.

4. The defendant shall have the burden of injecting the issue of retraction under subsection 3 of this section.

5. The offense of making a false affidavit is a class C misdemeanor, unless done for the purpose of misleading a public servant in the performance of his or her duty, in which case it is a class A misdemeanor.