The investigation revealed relentless activities directed toward Phoebe to make it impossible for her to stay at school,” Ms. Scheibel said. The conduct of those charged, she said, “far exceeded the limits of normal teenage relationship-related quarrels.” It was particularly alarming, the district attorney said, that some teachers, administrators and other staff members at the school were aware of the harassment but did not stop it. “The actions or inactions of some adults at the school were troublesome,” Ms. Scheibel said, but did not violate any laws.