492.303.  Essential witness, defined — deposition may be taken by prosecutor, procedure — costs — videotape authorized, used when. — 1.  Upon the hearing of an application by a prosecuting attorney, served upon an accused or his counsel not less than five days before the date the deposition will be taken, and a finding that the witness is an essential witness, the state may take the deposition of the witness.  A person is an "essential witness" if he is an eyewitness to a felony or if a conviction would not be obtained without his testimony because the testimony would establish an element of the felony that cannot be proven in any other manner.  An accused and his spouse are not essential witnesses under any circumstances.

  2.  The court shall make such orders in connection with the taking of the deposition as will fully protect the rights of personal confrontation and cross-examination of the witness by the defendant and shall make a finding that the prosecuting attorney has fully complied with all of his obligations involving discovery respecting the defendant and that the defendant has had sufficient time to adequately prepare for such deposition.  Upon application of the prosecuting attorney, the accused shall be ordered to attend the taking of the deposition.  The reasonable personal and traveling expenses of the accused and his counsel shall be taxed as costs and paid as provided by law.

  3.  The deposition may be taken if the witness is an essential witness. The deposition may be videotaped.  At the trial or upon any hearing, any deposition obtained in accordance with this section, so far as it is otherwise admissible under the rules of evidence, may be used by either party for any reason stated in Missouri supreme court rules of criminal procedure.  In addition, the deposition may be used by the state if the witness refuses to testify or fails to attend the trial or hearing if this refusal or failure to attend the trial or hearing is not produced by the action of the state.