Irrational Numbers (Bonnie Pinkwater series)

When her phone number is found in the pocket of a murdered student who previously came out of the closet in a speech to his classmates, full-time math teacher and part-time troublemaker Bonnie Pinkwater is drawn into the case. Joining forces with the school's principal, Lloyd Whittaker, Bonnie begins to investigate—only to have potential suspects start turning up dead. Using logic and math as a backbone of her investigation, Bonnie must catch the killer before she, too, is added to the growing list of bodies in this chilling casebook full of stunning twists and turns.