Western Springs police early Monday notified Lyons Township High School of a swatting call regarding the South Campus, authorities said.
Swatting is defined as the action or practice of making a prank call to emergency services in an attempt to bring out the dispatch of a large number of armed police officers to a particular address, according to Western Springs police.
While police determined the call to be a hoax, they conducted a sweep of the building, 4900 Willow Springs Road.
At 7:15 am, police completed the sweep and indicated that the building was safe and that school should start as scheduled.
As an added precaution, police will have increased police presence at South Campus throughout the day and at dismissal time.