Ohio Rev. Code § 2937.16: When witnesses shall be recognized to appear.

When an accused enters into a recognizance or is committed in default thereof, the judge or magistrate shall require such witnesses against the prisoner as he finds necessary, to enter into a recognizance to appear and testify before the proper court at a proper time, and not depart from such court without leave. If the judge or magistrate finds it necessary he may require such witnesses to give sufficient surety to appear at such court.