In some stories, the question remains unresolved of whether formal justice will ever be delivered, such as Five Little Pigs and Endless Night. According to P. D. James, Christie often, but not always, made the unlikeliest character the guilty party. Savvy readers could sometimes identify the culprit by simply identifying the least likely suspect.
On an edition of Desert Island Discs in 2007, Brian Aldiss claimed that Christie had told him that she wrote her books up to the last chapter, then decided who the most unlikely suspect was, after which she would go back and make the necessary changes to "frame" that person. However, John Curran's Agatha Christie: The Secret Notebooks describes different working methods for every book in Christie's bibliography, contradicting the claim by Aldiss.