Mo. Rev. Stat. § 595.223: Polygraph tests and psychological stress evaluator exams not permitted, when.

No prosecuting or circuit attorney, peace officer, governmental official, or employee of a law enforcement agency shall request or require a victim of an offense under chapter 566, or a victim of an offense of domestic assault or stalking to submit to any polygraph test or psychological stress evaluator exam as a condition for proceeding with a criminal investigation of such offense.