Wheaton North officials put the high school on heightened alert Friday after a threatening note was found in a student bathroom.
The bathroom was locked down for the remainder of the day, and Wheaton police and the DuPage County sheriff's police conducted a complete search of the building but found nothing, officials said.
Contact information ( * required )
As a precaution, extra Wheaton police officers remained on campus with the school resource officer.
Parents were notified via email Friday morning and school officials say an investigation will continue while students are on holiday break.