CHICAGO — An explosive revelation is shaking up an already competitive mayor’s race here after incumbent Lori Lightfoot’s campaign sent an email to Chicago public school teachers — in a system she oversees — asking them to recruit students to volunteer on her campaign for school credit. Now, the Chicago Public Schools inspector general is investigating the matter, critics are calling for more extensive inquiries and her opponents are piling on. “CPS OIG has opened an investigation into this matter and we are currently gathering information to determine which, if any, policies have been violated,” the Chicago Public Schools Office of Inspector General confirmed to NBC News Thursday. The probe comes after a deputy campaign manager sent an email to public school teachers — over government email — asking them to recruit students to volunteer for Lightfoot’s campaign in an “externship program” where students could earn class credit. As mayor, Lightfoot directly oversees Chicago schools, appointing the superintendent and members of the board of education.

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