N.Y. CPL Law § 620.30

§ 620.30 Material witness order; commencement of proceeding by\n application; procurement of appearance of prospective\n witness.\n 1. A proceeding to adjudge a person a material witness must be\ncommenced by application to the appropriate court, made in writing and\nsubscribed and sworn to by the applicant, demonstrating reasonable cause\nto believe the existence of facts, as specified in subdivision one of\nsection 620.20, warranting the adjudication of such person as a material\nwitness.\n 2. If the court is satisfied that the application is well founded,\nthe prospective witness may be compelled to appear in response thereto\nas follows:\n (a) The court may issue an order directing him to appear therein at a\ndesignated time in order that a determination may be made whether he\nshould be adjudged a material witness, and, upon personal service of\nsuch order or a copy thereof within the state, he must so appear.\n (b) If in addition to the allegations specified in subdivision one,\nthe application contains further allegations demonstrating to the\nsatisfaction of the court reasonable cause to believe that (i) the\nwitness would be unlikely to respond to such an order, or (ii) after\npreviously having been served with such an order, he did not respond\nthereto, the court may issue a warrant addressed to a police officer,\ndirecting such officer to take such prospective witness into custody\nwithin the state and to bring him before the court forthwith in order\nthat a proceeding may be conducted to determine whether he is to be\nadjudged a material witness.\n