No weapon was found after DuSable High School in the Bronzeville neighborhood was locked down and searched following reports of an armed person in the school.
About 2:45 p.m., police were at the school investigating the reports, according to Chicago Police. No injuries were reported.
By 5 p.m., police determined there was no active shooter and the lockdown was lifted, police said. Canines were at the school to conduct a final search.
Police said the incident might have stemmed from a prank call.