PITTSBURGH — A teen charged with stabbing 20 fellow students and a security guard at a Pennsylvania high school will be an adult by the time a hearing concludes to determine whether he should be tried in juvenile court.

Alex Hribal, of Murrysville, is charged with attempted homicide and aggravated assault as an adult even though he was just 16 on April 9, 2014. That’s when — in what defense psychiatrists say was an effort to emulate the Columbine school massacre — Hribal used two 8-inch kitchen knives to slash his way through the hallways of Franklin Regional High School.

Hribal’s attorney has been trying to get a Westmoreland County judge to move the case to juvenile court, where Hribal could face incarceration or probation only until he turns 21.

A hearing on that request began in June and was supposed to continue Monday, but District Attorney John Peck said it’s been postponed until Nov. 24 because a prosecution psychiatrist can’t testify until then. Hribal turns 18 on Oct. 1.