(1) Voluntary disclosure; informer as a witness. No privilege exists under this rule if the identity of the informer or his interest in the subject matter of his communication has been disclosed by the holder of the privilege or by the informer's own action, or if the informer appears as a witness for the state. Disclosure within a law enforcement agency or legislative committee for a proper purpose does not waive the privilege.

(2) Testimony on relevant issue. If it appears that an informer may be able to give relevant testimony and the public entity invokes the privilege, the court shall give the public entity an opportunity to make an in camera showing in support of the claim of privilege. The showing will ordinarily be in the form of affidavits, but the court may direct that testimony be taken if it finds that the matter cannot be resolved satisfactorily upon affidavits. If the court finds that there is a reasonable probability that the informer can give relevant testimony, and the public entity elects not to disclose this identity, in criminal cases the court on motion of the defendant or on its own motion shall grant appropriate relief, which may include one (1) or more of the following: