Topeka High School psychology teacher John Keller was "one of the best teachers I ever had," his former student, Isaiah Garinger, said in a Facebook post.
Keller, 39, was pronounced dead at a Topeka hospital, where he was taken after being found unresponsive shortly before 7:50 a.m. Tuesday in his classroom at the school at 800 S.W. 10th.
Further details regarding circumstances of his death weren't available Wednesday.
Keller was married, with three children, Principal Rebecca Morrisey indicated in an email sent early Tuesday evening informing parents of the school's students about his death.
"I am so very sorry for the loss we all feel," Morrisey wrote.
She indicated mental health professionals would be available to students who request them when they return from their Thanksgiving break.
Jennifer Antonetti, THS director of bands, expressed sadness in a Facebook post.
"He was a really great teacher, and this was a tragedy," she wrote. "Grabbing the AED (automated external defibrillator) from the office and giving it to the nurse this morning was a scary way to start the day."
This article originally appeared on Topeka Capital-Journal: Topeka High teacher John Keller dies at age 39, was found in classroom