No Designated Officer or an Investigation Officer or any other police officer or an officer of the Commission to Investigate Allegations of Bribery or Corruption who has acted on the instructions of a Designated Officer or an Investigation Officer, who has acted in good faith and diligently for the purposes of this Act, shall be liable in any suit or other legal proceedings for any lawful act which is done or purported to be done in good faith by such officer, in pursuance of the powers conferred by or under this Act, or for the purpose of carrying out the provisions of this Act.