Ohio Rev. Code Ann. § 2945.44 – Witnesses turning state's evidence

(A) In any criminal proceeding in this state or in any criminal or civil proceeding brought pursuant to Chapter 2981. of the Revised Code, if a witness refuses to answer or produce information on the basis of the witness's privilege against self-incrimination, the court of common pleas of the county in which the proceeding is being held, unless it finds that to do so would not further the administration of justice, shall compel the witness to answer or produce the information, if both of the following apply:
1. (1) The prosecuting attorney of the county in which the proceedings are being held makes a written request to the court of common pleas to order the witness to answer or produce the information, notwithstanding the witness's claim of privilege;
2. (2) The court of common pleas informs the witness that by answering, or producing the information the witness will receive immunity under division (B) of this section.
(B) If, but for this section, the witness would have been privileged to withhold an answer or any information given in any criminal proceeding, and the witness complies with an order under division (A) of this section compelling the witness to give an answer or produce any information, the witness shall not be prosecuted or subjected to any criminal penalty in the courts of this state for or on account of any transaction or matter concerning which, in compliance with the order, the witness gave an answer or produced any information.
(C) A witness granted immunity under this section may be subjected to a criminal penalty for any violation of section 2921.11, 2921.12, or 2921.13 of the Revised Code, or for contempt committed in answering, failing to answer, or failing to produce information in compliance with the order.