You perceive the devilish cunning of it, for really it would be almost impossible to make a case against the real murderer.

His only accomplice was one who could never give him away, and the grotesque, inconceivable nature of the device only served to make it more effective.

Both of the women concerned in the case, Mrs.Stapleton and Mrs.Laura Lyons, were left with a strong suspicion against Stapleton.

Mrs.Stapleton knew that he had designs upon the old man, and also of the existence of the hound.
Mrs.Lyons knew neither of these things, but had been impressed by the death occurring at the time of an uncancelled appointment which was only known to him.

However, both of them were under his influence, and he had nothing to fear from them.