MOUNT VERNON, Wash. -- A 16-year-old boy is in juvenile detention after he allegedly threatened to commit a mass shooting at Mount Vernon High School on the first day of school.

Students tipped off their parents after the boy posted warnings of a "Columbine attack" on his Facebook profile Friday.

Mount Vernon Police Lieutenant Chris Cammock says students on Facebook took the threats seriously.



The boy has a history of contact with police.

Officials say he has anger issues and suffers from unpredictable behavior.

He was arrested Saturday.

The boy is not currently a student at any Mount Vernon school.