Celina High School was placed on soft lockdown Monday morning after a suspicious note was found on campus.
During a soft lockdown, students are permitted to move around within the school, but no one is allowed in or out of the building.
Celina Independent School District Superindendent Donny O'Dell said the note was found at the high school and pertained to the staff, but did not reveal what the note said or where specifically it was found.
O'Dell said the school was placed on soft lockdown until about 1 p.m.
The school remains on a normal schedule.