AThis FAQ entry is a work in progress.Denny's wife Madeleine murders him. She serves him water she knows is infected with typhoid. Dr. Bickleigh had lectured her frequently about her poor sanitation, which gave her the idea.Bickleigh commits his own murders but is tried for them and acquitted. Instead, he is hanged for Madeleine's crime. A typhoid-carrying fly lands on his botulin cultures and implicates him. The police find the typhoid bacteria in his incubator.