GREENSBURG — A judge says a teen who was just 16 when he stabbed 20 students and a security guard at his suburban Pittsburgh high school should stand trial as an adult, not in juvenile court.

The defense attorney for Alex Hribal had argued juvenile court supervision — which would end when he’s 21 — would provide a better chance for the suspect to receive treatment for mental health issues that fueled his rampage at Franklin Regional High School in Murrysville in April 2014.

But Westmoreland County Judge Christopher Feliciani agreed with District Attorney John Peck that the enormity of the attacks — and the risk Hribal could re-offend — make adult sanctions appropriate.