HIXSON, Tenn. -- Monday, students at Hixson High went to school without one of their classmates.
The Hamilton County Sheriff’s Office says a man shot and killed his 15-year-old son over the weekend.
Deputies say the father admitted to the crime when police found him across the street here naked, on his neighbor's front porch.
That's hard to explain to anyone, let alone teenagers.
An arrest affidavit details Michael McElrath telling deputies, "I did it.. I'm so sorry.. I shot my son.. and I don't know why."
Patricia Russell oversees the counselors now helping kids at Hixson High School.
Just a week into the school year, they lost a 15-year-old honor student and friend.
"I've heard some outstanding stories," she said. "I've heard that he is well-mannered."
Russell says no one saw this coming.
According to the arrest report, McElrath also shot the family's dog after telling his wife, "It was nothing. It was a dream."
Lingering on McElrath's Facebook page are posts from days before the shooting.
In one he says, "For all my friends I haven't talked to while facing my demons, I'm baaaaaaaaaaack."
His profile also manages a blog page that details a battle with chronic pain and a condition called “complex regional pain syndrome.”
It even lists plans to amputate both legs and climb the highest mountain in the US.
Investigators haven’t said if any medical condition played into this case.
Either way, it's a devastating loss that's hard to explain.
"They're all our kids," Russell said. "Our staff is all one big family, so when one of us hurts, all of us hurt."
The school says they put out a banner students can express memories on through writing or drawing.
They will stay up as long as needed to grieve the loss.
NewsChannel 9 also learned Monday that McElrath worked as airport police until 2002, as well as a corrections deputy for three years in the '90s.
Depend on us to keep you posted as we learn more about this case.