Each educational service district superintendent shall cause to be investigated all written and signed complaints, from whatever source, that allege that a certificated education professional within his or her educational service district is not of good moral character or personal fitness or has committed an act of unprofessional conduct. If the educational service district superintendent investigates and determines the facts are reliable and further investigation by the superintendent of public instruction is warranted, the educational service district superintendent shall forward the written complaint and the results of his or her investigation to the superintendent of public instruction: Provided, That if the educational service district superintendent, after consultation with the assistant attorney general assigned to his or her educational service district, determines that the substance of the complaint would not constitute grounds for reprimand, suspension, or revocation if true, then such educational service district superintendent need not investigate the complaint: Provided further, That if the educational service district superintendent receives a written assurance from the superintendent of public instruction, a district superintendent, or a chief administrative officer of an approved private school that such official is investigating or will investigate the same or a substantially similar complaint, the educational service district superintendent shall be deemed to have caused an investigation in compliance with this section.