Officials have confirmed that a suspect was taken into custody.
The suspect, a former student, was the subject of jokes from other kids, according to a student at the school.
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A student told WFOR-TV that other students "knew it was going to be him."
"A lot of people were saying it was going to be him. A lot of kids threw jokes around saying that he was going to be the one to shoot up the school," the student said. "It turns out that everyone predicted it. That's crazy."
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Seventeen-year-old junior Matthew Walker spoke to ABC News, saying the suspect was known to show off knives and guns.
"He was going class to class just shooting at random kids," he said. "Everything he posts (on social media) is about weapons. It's sick."
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