As used in this title:
(a) “Witness” means any person who has been summoned, or is reasonably expected to be summoned, to testify in a criminal matter, including grand jury proceedings, for the people whether or not formal legal proceedings have been filed. Active or passive participation in the criminal matter does not disqualify an individual from being a witness. “Witness” may also apply to family, friends, or associates of the witness who are deemed by local or state prosecutors to be endangered.
(b) “Credible evidence” means evidence leading a reasonable person to believe that substantial reliability should be attached to the evidence.
(c) “Protection” means formal admission into a witness protection program established by this title memorialized by a written agreement between local or state prosecutors and the witness.