Probably something personal. And the black trenchcoat may just indicate that he is another troubled kid that hates the world and identified with columbine. Certainly seems odd for a homeschooled kid.
As the past leader of my county homeschool association and also one who has been active on the state level, I can tell you that the face of homeschooling is changing. Under no child left behind, our local school system has begun advising parents of at risk and problem students that homeschool might be a “good” option for them.
My godson styruggled with reading and when he tested at low 6th grade levels even though he was in the 9th grade, the school system suggested that maybe he neeeded to homeschool. I advisedd her to tell them they created the problem they needed to solve it.