Mo. Rev. Stat. § 434.080: Interrogatories.

In all suits under this chapter, the plaintiff may call upon the defendant to answer, on oath, any interrogatory touching the case in the manner and form prescribed by the rules of civil procedure, and if the defendant shall refuse to answer, the same shall be taken as confessed; but such answer shall not be admitted as evidence against such person in any criminal proceedings by indictment or by information.