Whenever any law enforcement official of the state or any city or town determines that a person who is: (1) incarcerated upon conviction for a felony; (2) indicted or informed against for a felony; or (3) the subject of a felony investigation; is willing to give evidence regarding the commission of felony offenses within the state in exchange for a reduction of his or her sentence, assistance in obtaining parole, the dismissal or reduction of charges pending against him or her, and/or immunity from prosecution, the official shall immediately notify the attorney general. An assistant attorney general and the law enforcement official shall interview the prospective witness to determine what information he or she possesses and what consideration he or she is seeking for his or her testimony. If they determine that the evidence proffered is reliable and that the consideration sought is reasonable, the assistant attorney general shall prepare a written memorandum setting forth all of the terms of the agreement which shall be signed by the witness, a representative of the law enforcement agency initiating the case, and representative of the attorney general’s office. The terms of the agreement shall include the length and manner of custodial supervision to be provided in order to accomplish both the protection and incarceration of the criminal witness. The document shall explicitly state that the agreement will become void if the criminal witness violates the terms of his or her confinement, fails to provide the promised information and assistance to the prosecution, or commits a new crime. The prospective witness shall be afforded the right to counsel during the negotiation and execution of the agreement. The memorandum shall not become binding and enforceable by the parties until approved in accordance with the procedures set forth in § 12-30-3.