Union High School was evacuated Monday morning after school officials were notified of a threat scrawled on a bathroom wall.
Union R-XI School Superintendent Steve Bryant said police and fire crews responded to the school after 10:30 a.m. A sweep of the school was conducted after the threat was found, but there was nothing located.
Bryant said that school officials were close to identifying who wrote the message, but then there was a power outage at the school. That is when the school was evacuated.
He noted that the power outage is unrelated to the threat. Students had returned to class by 11:15 a.m.
Teachers will conduct a secondary sweep of the school and district officials are preparing a message to be sent to parents.
"We have taken all of the proper precautions, and done all of the normal procedures," Bryant said. "We will continue to monitor this all day long, but we didn't find anything to cause alarm."