MURRYSVILLE, Pa. -- The attorney for a 16-year-old charged in a stabbing spree at his Pittsburgh-area high school says he wants to have a mental health expert evaluate the boy.

The attorney also says he's hoping to move the criminal charges against Alex Hribal to juvenile court. For now, Hribal is charged as an adult with attempted homicide, aggravated assault and a weapons charge in Wednesday's attack at Franklin Regional High School in Murrysville. Twenty-two people were injured.

In an interview Thursday with ABC's "Good Morning America," defense attorney Patrick Thomassey acknowledged that Hribal stabbed the victims and said he didn't know what motivated him. He said Hribal is remorseful but didn't appear to appreciate the gravity of his actions.

And he said Hribal's parents were "horrified" by the attack.