JACKSON TWP — A bomb threat left in a classroom building in the Seneca Valley Intermediate High School affected extracurricular activities Thursday afternoon. An emergency alert e-mailed to parents by district Superintendent Tracy Vitale said the written threat was left in a classroom and included a specific time for late in the afternoon and after school dismissal. Administrators either canceled or relocated extracurricular activities that were to take place at the school. Vitale said Jackson Township Police were reviewing surveillance equipment and conducting an investigation. Specially trained K-9 units were brought in to sweep the building. No bomb was found and classes were held Friday.