§ 620.30 Material witness order; commencement of proceeding by application; procurement of appearance of prospective witness. 1. A proceeding to adjudge a person a material witness must be commenced by application to the appropriate court, made in writing and subscribed and sworn to by the applicant, demonstrating reasonable cause to believe the existence of facts, as specified in subdivision one of section 620.20, warranting the adjudication of such person as a material witness. 2. If the court is satisfied that the application is well founded, the prospective witness may be compelled to appear in response thereto as follows:

(a) The court may issue an order directing him to appear therein at a designated time in order that a determination may be made whether he should be adjudged a material witness, and, upon personal service of such order or a copy thereof within the state, he must so appear.

(b) If in addition to the allegations specified in subdivision one, the application contains further allegations demonstrating to the satisfaction of the court reasonable cause to believe that (i) the witness would be unlikely to respond to such an order, or (ii) after previously having been served with such an order, he did not respond thereto, the court may issue a warrant addressed to a police officer, directing such officer to take such prospective witness into custody within the state and to bring him before the court forthwith in order that a proceeding may be conducted to determine whether he is to be adjudged a material witness.