Now, other places like Bloomington High School are putting the incident on their radar.
District 87 Superintendent Barry Reilly says the unexpected situation has prompted him and building leaders to look over their crisis procedures.
All buildings have emergency plans in place, but he believes they can be made safer.
District 87 has made contact with Unit Five's superintendent in order to discuss issues together.
"We will get together and I'll learn what I can from him and his debrief," said Dr. Reilly. "We'll also communicate with the police departments as well. So, there are lessons to be learned for all of us."
Meantime, Normal Community is also improving its security measures.
It's even considering having metal detectors at school.