During the shooting at Oxford High School on Tuesday, the school issued what's called an ALICE lockdown that was announced over the speakers.
The alert system played so that staff and students knew to immediately go into lockdown.
It stands for:
Alert — Becoming aware of the threat, the sooner you're informed, the better.
Lockdown — Barricading entries to rooms, if you cannot escape a building.
Inform — Communicating the intruder's location and direction in real time.
Counter — Encourages people to make noise or create a distraction with the intent of reducing an attacker's ability to accurately shoot. (This does not mean fighting).
Evaluate — Get yourself out when it's safe to do so.
According to the district's website, the last drill was held at Oxford High School just two months ago in October.
The Oakland County Sheriff's Office said the system and all other systems in place helped officers on scene, as well as staff and students.