What is the author's style in In the Garden of the North American Martyrs by Tobias Wolff?

"In the Garden of the North American Martyrs" is presented to readers in third-person omniscient narration. The narrator describes Mary's past in order to clarify her present situation. In the first part of the story, the narrator appears to regard Mary indifferently or even negatively. As the narrative progresses, however, Mary is presented more sympathetically and— importantly— Louise and some other characters are shown in a very bad light. Wolff subtly shifts the point of view. He explained in an interview with Jay Woodruff in 1991 that he always intended to let Mary take over the narration, that his "aim was to hand the story over to her." He goes on to say that this shift in point of view was necessary because her voice needs to dominate the narrative by the time she gets to her dramatic concluding speech.