What is the narrative point of view in "The Possibility of Evil"?

The story is told by an anonymous, omniscient narrator and almost entirely from the point of view of the protagonist Miss Strangeworth. This is established at the very beginning.

Miss Adela Strangeworth stepped daintily along Main Street on her way to the grocery. The sun was shining, the air was fresh and clear after the night’s heavy rain, and everything in Miss Strangeworth’s little town looked washed and bright. Miss Strangeworth took deep breaths, and thought that there was nothing in the world like a fragrant summer day.

The quoted paragraph tells what Miss Strangeworth does, sees, thinks and feels. Although the reader is in her point of view throughout most of the story, he still doesn't necessarily understand her. She is obviously more than a little bit crazy. This is brought out clearly when she writes her three anonymous letters. She observes that many of the people in her little town seem "troubled" lately, but she cannot understand that there could be any connection between these troubles and her letters. She doesn't understand her own motives. She thinks she is doing her civic duty as the town's leading citizen by warning others of "the possibility of evil."

The only departure from Miss Strangeworth's point of view occurs when she accidently drops one of her poison-pen letters in front of the post office. Normally it is important for an author to remain in a character's point of view because that is how the reader "gets into the story." If it should be necessary to switch to a second character's point of view, then the author has to reestablish reader identification with that character and should remain in his or her point of view. When Miss Strangeworth drops the letter in the pink envelope intended for Don Crane, young Dave Harris picks it up, and the reader is temporarily in his point of view. Miss Strangeworth has departed from the scene. This switching to Dave Harris's point of view is necessary for plot purposes. It is permissible because it focuses entirely on Miss Strangeworth and her letter. It is noteworthy that although Dave Harris delivers the letter to the addressee, the reader is never placed in Don Crane's point of view, although we can well imagine how Don feels when told by Dave and Linda that Miss Strangeworth dropped it in front of the post office and he reads the contents:

Didn’t you ever see an idiot child before? Some people just shouldn’t have children, should they?

What Don Crane feels, thinks, and does is shown from Miss Strangeworth's point of view.

Her hand did not shake as she opened the envelope and unfolded the sheet of green paper inside. She began to cry silently for the wickedness of the world when she read the words: Look out at what used to be your roses.

Miss Strangeworth does not know who destroyed the rose bushes and sent her the anonymous letter--but we know!