GRAND BLANC -- Grand Blanc High School and two middle schools have received an anonymous bomb threat for the first day of school.

A letter on the school district's web site says buildings will be searched for evidence of explosive devices over the weekend.

Once searched, the building will be locked until tuesday, the first day of school.

In the letter, the district says: "Local police and other emergency agencies have been contacted and are working with the school district to ensure the safety of our students and staff the first day of school and throughout the entire year."