R.I. Gen. Laws § 12-16.1-6: Prisoner from another state summoned to testify in this state.

(a) If a person confined in a penal institution in any other state may be a material witness in a criminal action pending in a court of record or in a grand jury investigation in this state, a judge of the court may certify:

(1) That there is a criminal proceeding or investigation by a grand jury or a criminal action pending in the court;

(2) That a person who is confined in a penal institution in the other state may be a material witness in the proceeding, investigation, or action; and

(3) That the person’s presence will be required during a specified time.

(b) The certificate shall be presented to a judge of a court of record in the other state having jurisdiction over the confined prisoner, and a notice shall be given to the attorney general of the state in which the prisoner is confined.