Mo. Rev. Stat. § 544.020

Whenever complaint shall be made, in writing and upon oath, to any associate circuit judge setting forth that a felony has been committed, and the name of the person accused thereof, it shall be the duty of such associate circuit judge to issue a warrant reciting the accusation, and commanding the officer to whom it shall be directed forthwith to take the accused and bring him before such associate circuit judge, to be dealt with according to law. The complaint may be made and the warrant may be issued via facsimile or other electronic means.