Addison High School participates in active shooter drill

Students participate in an active shooter drill at Addison High School.

Addison High School was on lockdown Thursday for an active shooter, but it was just a drill.

School officials staged a fake shooting so theyâ??ll be ready if the real thing happens.

The drill is often performed by emergency crews in empty schools during the summer. On Thursday, Addison asked their students to participate.

For over an hour, state police and emergency agencies swarmed the building in pursuit of three state troopers portraying gunmen.

The school is preparing for the worstâ??the kind of tragedy that left four dead, including a gunman, at the Fort Hood Military Base in Texas on Wednesday.

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Craig Tanis of Michigan Homeland Security helped plan the drill at Addison High School. â??Itâ??s going to happen,â?? Tanis said. â??Itâ??s not a matter of if but when and if we can be more prepared for it, we can save lives.â??

Teachers went as far as barricading their classroom doors in drills so realistic that some parents hesitated to let their kids participate. Superintendent Steve Guerra excluded middle school and elementary students from the exercise. â??Some of the parents were worried about seeing their young children seeing sirens, hearing gunshots, hearing screaming,â?? Guerra said.

Students volunteered to be victims and had their wounds painted on by a professional makeup artist. Fake blood and bullet casings were scattered throughout the hallway.

School officials are considering repeating the drill every four years, so every student participates in the drill once.