Unnatural Death (Lord Peter Wimsey)

The plot concerns Lord Peter's investigation into the death, three years earlier, of an elderly lady in the last stages of cancer. The lady's death has aroused no suspicion, despite her doctor's dismay at her end coming so quickly, but Wimsey suspects that it may, after all, have been 'unnatural'. The difficulty of discovering the method is compounded by the difficulty of discovering someone with the motive and opportunity to kill.