“Now what was that object? You heard my arguments tonight in reference to the scrap of conversation overheard? As soon as I learned that a representative of a dictaphone company had called, the idea of a dictaphone took root in my mind. You heard what I said in this room not half an hour ago? They all agreed with my theory⁠—but one vital fact seems to have escaped them. Granted that a dictaphone was being used by Mr. Ackroyd that night⁠—why was no dictaphone found?”

“I never thought of that,” I said.