A security guard wounded trying to stop a student who had just stabbed 20 others at a western Pennsylvania high school has died.

Seventy-one-year-old John Resetar, of North Huntingdon, died of a heart attack Thursday morning at a hosptial in Greensburg.

Resetar was stabbed in the abdomen as he and others subdued Alex Hribal (RY'-bal) who has slashed his way through the hallways of Franklin Regional High School in Murrysville before classes began on April 9, 2014.

Hribal's attorney has acknowledged Hribal — then 16 — stabbed Resetar and 20 students. He's charged as an adult in Westmoreland County, though his attorney is trying to get the case moved to juvenile court.

The Westmoreland County coroner and Resetar's attorney, Tim Dawson, confirmed his death.