“There is one further point. The murderer must have been a person who had the opportunity to purloin that dagger from the silver table. You might argue that anyone in the house might have done so, but I will recall to you that Miss Ackroyd was very positive that the dagger was not there when she examined the silver table.”

He paused again.

“Let us recapitulate⁠—now that all is clear. A person who was at the Three Boars earlier that day, a person who knew Ackroyd well enough to know that he had purchased a dictaphone, a person who was of a mechanical turn of mind, who had the opportunity to take the dagger from the silver table before Miss Flora arrived, who had with him a receptacle suitable for hiding the dictaphone⁠—such as a black bag, and who had the study to himself for a few minutes after the crime was discovered while Parker was telephoning for the police. In fact⁠— Dr. Sheppard !”