(CNN) -- No one knows why he picked this day, this time, these victims.
It was the first day back from fall break at Sparks Middle School. Students milled about, waiting to hear the morning bell.
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Within moments, two 12-year-old students were wounded. A beloved teacher and military veteran lay dead. And the young shooter -- armed with his parents' gun -- took his own life, silencing any way of understanding what he was thinking.