In "A Rose for Emily," why did Emily kill her husband?
Homer was not Miss Emily's husband, and this could be one reason why he was killed! Homer apparently never had any intentions of marrying Emily, and stated this to some men at a bar in town. It could be for this very reason that Emily bought the bottle of arsenic.
Emily's father was very strict when he was raising her, and he chased off all the young suitors because he felt they were not good enough. Emily could have felt that Homer was her last chance at marriage, and when she discovered that he was not in it for the duration she could have snapped.
Emily already had issues about people leaving her. After her father died, she refused to let them take his body for a time. It appears Miss Emily would have done anything to hang on to Homer, including killing him.