WARREN, Mich. -

A threat at a high school in Warren on Wednesday led to a brief lock down before students were dismissed.

Fitzgerald Public Schools superintendent Barbara VanSweden said a teacher and a student reported seeing the threat on Twitter and reported it to the principal. Officials put their lock down procedures into place -- which meant students and staff remained in classrooms until Warren police had cleared the building.

Warren police at Fitzgerald

No weapon was found, VanSweden said.

Students were released at 1:45 p.m.

The school is located on Ryan Road near 9 Mile.