On 29 December 1962, Mrs Sheridan Pausey, of Windswept Dachshund Kennels, gave Margaret Chandler some Hydarex tablets to treat her puppies for worms. She warned Mrs Chandler that the tablets were dangerous for humans.
The theory subscribed to by Daily Mirror crime reporter Bill Jenkings, and Detective Sergeant Jack Bateman, nicknamed the "Father Confessor", was that Bogle and Chandler were victims of a practical joke. Jenkings, in his autobiography, refused to name the person he thought had played the joke on the grounds that the person was still alive. There can be little doubt, however, that the person he was referring to was Geoffrey Chandler.
The theory was that Mr Chandler, ignorant of the dangerous nature of the dog tablets and being aware that his wife and Dr Bogle would be having a romantic liaison, decided as a joke to add the tablets to their coffee. The tablets would cause bowel looseness, vomiting and other symptoms, interrupting the couple but without intent to cause permanent injury. Unfortunately, so this theory goes, the tablets were more potent than Mr Chandler had thought, and both his wife and Dr Bogle died.
According to Geoffrey Chandler in his book So you think I did it, analysis of the dog tablets showed that the dangerous element of the tablets was a substance called arecoline hydrobromide. Mr Chandler said that analysis failed to detect this substance in either body. Whether the technology existed to detect it is a another matter.
What was lacking was any reason for Mr Chandler to be playing a practical joke. Chandler had never objected to any of his wife's romantic liaisons in the past, so why now, where the effect would be to embarrass her in front of a man for whom she expressed admiration? Similarly, there is no record of Chandler being a man prone to performing practical jokes, so why start with this?
Other speculation: