What techniques does the author use to show saul being haunted

We actually see Saul haunted throughout the narrative. In chapter 11, Sister Ignacia tells Saul what the school is meant to do. She smiled again with the same ghastly lack of feeling. “At St. Jerome's we work to remove the Indian from our children so that the blessings of the Lord may be evidenced upon them.”

Saul then simply exists at the school. He lives like a ghost: the art of being unseen, until he discovers hockey.