A 74-year-old woman who was recovering from surgery at a Maryland hospital was stabbed to death with a pen by a 15-year-old psychiatric patient who witnesses said had a “blank” and “unemotional” facial expression, police said. The incident took place at the University of Maryland Medical Center last Wednesday, but the hospital first disclosed details about the attack on Friday. The suspect, Andrew Gaudet, has been charged as an adult with attempted murder in the death of Kathleen Walker. Gaudet reportedly bolted past a hospital employee who was supposed to be monitoring him before allegedly stabbing Walker in the face and punched her, police said. Gaudet also allegedly punched a nurse multiple times in the face as hospital employees tried to haul him away. Walker, who was a retired school teacher, died the following day in the hospital’s shock trauma center.