The Northbrook high school's community was first rocked Wednesday when a student found a message written on top of a desk that read, "Shooting 10 03." The school administration and Northbrook police immediately began investigating, GBN principal John Finan said in an email to students and parents.
Finan said GBN staff members thoroughly inspected the school, including students' lockers, Wednesday evening, and the school put additional security measures in place as classes resumed Thursday. Students were told not to arrive at school prior to 7 a.m. and all students' and visitors' belongings were to be searched upon entry. Finan said Northbrook police would also be present on campus Thursday.
At about 8 a.m. Thursday, after what Finan called an "efficient and safe student arrival process," the school was evacuated due to a fire alarm. In an email to parents, Finan said the source of the alarm was an electrical motor in the HVAC system that had burned out. Students and staff re-entered the school and resumed classes once the alarm was deactivated.
About three hours later, GBN parents received another email from Finan notifying them that a second threatening message was found carved into a chair in a classroom that read, "Stay out of school 10 4." Finan said there was also the image of a handgun etched below the message.
All school events Thursday were to continue as scheduled with increased security measures, Finan said.
The threats at GBN come one week after a threat was found at the school's sister school, Glenbrook South High School. That threat was later found to be not credible.