Classes at Biddeford High School were canceled this morning after a bomb threat. A school custodian discovered a note on a door about 6:15 a.m., which mentioned a specific time for carrying out the threat.

The majority of students were already on their way to the school when the events occurred, said superintendent Sarah-Jane Poli. All students on bus routes were dropped off at Biddeford Middle School, where they waited in the school auditorium. At about 8:15 a.m., high school students at the middle school were returned by bus to their homes. Students driving to school were told to return home.

Students were scheduled to have an early release day today. Poli said the school may schedule a make-up day.

If a student was involved in the incident, he or she will appear in front of the school committee for an expulsion hearing, Poli said. The Biddeford police were also notified.

Teachers participating in staff development this morning initially met at the Regional Center of Technology building, but were able to return to the school by 9:45 a.m., Poli said.