A threatening photo and message posted Monday on Snapchat resulted in a flurry of activity at Mahtomedi High School, but the student who posted the message wasn't in school and an investigation revealed staff and other students weren't in danger, said Superintendent Mark Larson.

"We commend the actions of fellow students in alerting their parents to the social media posting," Larson said in a message sent to district families. "Fellow students who saw the message immediately alerted their parents and the authorities were called. We want parents, staff and students to know that the Washington County Sheriff's Department has been in contact with the student and the student's parents."

The nature of the threat wasn't disclosed.

Mahtomedi High School, in Washington County, has an enrollment of about 1,200 students in grades 9-12. Deputies stood guard in the high school and middle school parking lots as a precaution Monday and the case is under investigation, Larson said.

Parents may contact school with any questions, he said.

Kevin Giles