Immunity; Discharge of Co-Respondent/Accused to be a Witness. - Any public official or employee or any person having been charged with another under this Act and who voluntarily gives information pertaining to an investigation or who willingly testifies therefore, shall be exempt from prosecution in the case/s where his/her information and testimony are given. The discharge may be granted and directed by the investigating body or court upon the application or petition of any of the respondent/accused-informant and before the termination of the investigation: Provided, That: