L’Anse Creuse North went on lockdown around 11:30 a.m. Wednesday after a teacher found a student’s notebook that had disturbing messages and bomb-making instructions.

The Macomb County Sheriff’s Department responded to the school’s call, and they confiscated the notebook and searched the student’s locker.

Students were allowed to go home when the lockdown was lifted in the afternoon.

The student and the family are cooperating with the investigation, Macomb County Sheriff Anthony Wickersham said. No arrests have been made.

No specific threats were made, but the investigation will continue, the sheriff said.