MURRYSVILLE, Pa. (AP) — Teachers have returned to a Pittsburgh-area high school where 21 students and a security guard were wounded in a stabbing rampage five days ago.

They attended a counseling session at a church Monday morning before heading over to Franklin Regional High School in Murrysville.

Students will be able to visit the school with their families Tuesday and classes will resume Wednesday, a week after the attack.

Four students remain hospitalized in critical condition.

Authorities say 16-year-old Alex Hribal attacked his fellow students at the school with a pair of kitchen knives. He faces four counts of attempted homicide and 21 counts of aggravated assault.

A motive for the attack remains unknown. The boy's lawyer is seeking to have him undergo a psychiatric evaluation.