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, but there can be little doubt that he was referring to 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. Apparent evidence to back up this theory was the fact that the puppies still suffered from worms in the new year. Mrs Pausey was of the opinion that this would not have been the case had the tablets been used as intended.
The theory that Dr Bogle and Mrs Chandler were poisoned using dog worming tablets remains popular, but was in fact addressed briefly during the inquest: 22
Sgt Goode: Do you remember on December 29, Mrs Chandler came to your place with two or three of her dogs?
Mrs Pausey: Yes. The puppies were suffering from worms.
Sgt Goode: You recommended to her that she should use Hydraex tablets for their treatment?
Mrs Pausey: Yes.
Sgt Goode: Did you explain to her the correct dosage for the dogs?
Mrs Pausey: Yes, and I cautioned her that they are very dangerous to humans. Whenever I gave it I cautioned everyone because they are rather like headache pills.
Sgt Goode: Did you give her tablets for her dog?
Mrs Pausey: Yes. I think five.
Sgt Goode: On that day how did Mrs Chandler seem to you?
Mrs Pausey: She was not quite herself.
Sgt Goode: After Mrs Chandler’s death did you receive a telephone call from Mr Chandler about the dogs?
Mrs Pausey: Yes.
Sgt Goode: Were they suffering from worms?
Mrs Pausey: Yes. I wormed them subsequently.
Sgt Goode: Had the dogs been given the Hydarex tablets towards the end of December, would they have been in the condition they were in in relation to worms in February?
Mrs Pausey: I don’t think so.
Sgt Goode: In view of inquiries made, did you give the police information about the tablets you had supplied?
Mrs Pausey: Yes.
Sgt Goode: (to Coroner) I think I should say at this stage that this matter of the Hydarex tablets, after our conversation with Mrs Pausey, was investigated by the analysts and the report has been tendered here as an exhibit. They made extensive inquiries, and as far as they were able to see, there was no trace of whatever toxic substance it contained. They couldn’t find it.
Geoffrey Chandler, who had access to the analysts' report, said later in his book So you think I did it that analysis of the dog tablets showed the dangerous element to be a substance called arecoline hydrobromide. This was not detected in either body. Of course, it may be that the testing methods available in 1963 were not advanced enough to be able to detect it. This is now known to be the case for another of the suspected poisons, LSD.
Perhaps a more potent criticism of the theory is the lack of a convincing motive. There is no record of Mr Chandler performing practical jokes, and while his attitudes to sex and marriage may have been considered odd, there was never any suggestion that he was a hypocrite -- he considered his wife free to do as he did himself. He'd never objected to his wife's romantic liaisons in the past, so why start now, when the effect would be to embarrass his wife in front of a man for whom she'd expressed admiration?
Other speculation: