Susan Glaspell’s Trifles: How Dramatic Irony Provides an Extra Dimension to the Mystery and Show Examples of What We as the Audience Know That Some Characters Do Not
Wright loved the bird, so they and the audience should make the assumption that Mr. Wright killed it. This deduction together with the other evidence of Mrs. Wright's growing instability (like the terrible sewing) lead the women and audience to believe in Mrs. Wright's guilt and the reason she killed her husband. This situation represents dramatic irony because the sheriff and county attorney remain oblivious to these clues, so the audience knows more than they do about the crime.
In reality, it is they who trifle about Minnie Wright's housekeeping, while Mrs. Peters and Mrs. Hale solve the mystery of why Minnie Wright killed her husband. As a final twist, the two women end up identifying with Minnie Wright’s abuse at the hands of her husband and feel the murder was justified. They then conspire to conceal the truth from their ignorant husbands and the county attorney.