 The fingerprints on the dagger are yet to be tested but Poirot has a theory that they will find only the dead man's prints on the handle.The missing letter from Mrs Ferrars is also a puzzle and Poirot summons Parker and asks him to state what is different about the study compared to when he helped break in the previous evening.Parker tells him of the differences – including the fact that the armchair was pulled out from its normal position and turned at a strange angle, something that catches Poirot's attention.