Mo. Rev. Stat. § 545.400: Conditional examination of witnesses.

The defendant in any criminal cause may also have witnesses examined on his behalf, conditionally, upon a commission issued by the clerk of the court in which the cause is pending, in the same cases and upon the like notice to the prosecuting attorney, with the like effect and in all respects as is provided by law in civil suits; provided, that the notice in such case to the prosecuting attorney shall state the name or names of the witness or witnesses whose depositions are desired or will be taken.