A bomb threat forced the evacuation of Waseca junior and senior high schools early Monday afternoon, school and police officials said.
A student reported seeing a bomb threat written on the wall of a bathroom stall, prompting the evacuation of about 620 students just after 12:30 p.m.
"In today's world, we have to take everything seriously," Waseca Superintendent Tom Lee said. "In the end, we were able to evacuate the building. I feel like our kids are safe."
Lee said police and district staff were in the school Monday afternoon, looking for anything that might seem suspicious or out of place, and bomb-sniffing dogs were on their way.
Investigators will be looking at video footage from the school and will interview people seen coming and going from the restroom.
"We'd like to give the all-clear to go back to school tomorrow, but we want to be absolutely sure it's safe," Lee said.
"Probably 99.9% of the time it's going to be a kid trying to get out of something, but we have to take that .1% seriously."