This was the discovery of the body of an ordinary bat found lying in a dark corner of the room. The creature was dead—it had apparently been crushed when some furniture had been moved, possibly by the doctor's direction.
Mr. Potter carefully picked up his curious find, and placed it in a cardboard box on which his eye chanced. The box he placed on a high shelf in a convenient cupboard. It might, he thought, prove useful in the future.
Confident though he was of Laurence's guilt, he determined not to be rash. To start from the beginning was his intention. And so his first move was to interview Moggin, the coachman, to whom he introduced himself as the "nurse." Cautiously guiding the conversation on to the subject of highwaymen of the present time, he was rewarded by a confidential description of the attack on the carriage, that had happened a few days before. Moggin had, of course, learned of the injury that had befallen his master, and confessed that he connected the two attacks with one another, as having been made by the same man.
Mr. Potter was annoyed. The coachman was certainly telling the truth. He had deemed it possible that Moggin might have been an accomplice in the so-called attack, and that no "highwayman"—not even another accomplice in disguise—had existed. This was evidently not the case. Ergo, there must be some other man in league with Laurence. This other accomplice was a very important person. He had, according to the detective, not only played the highwayman, but also the market-woman whom Miss Scott had decided was a man disguised.
Oliver Potter was at a loss to know what step to take next. Strange to say, it never entered his head to visit Durley Dene. In his confidence that he was on the right track, he evidently had little doubt but that the neighbouring mansion was uninhabited. For who knew anything about the persons that lived there? Only Laurence! Of course, the message that had been sent by means of a catapult from the grounds of the Dene had been despatched by the accomplice on whom Potter was so anxious to lay his hand.
Then a brilliant idea struck the man from Burton's. Was Selene Scott that accomplice? Might not she have attacked the carriage on the moor? Might not the story of the market-woman in disguise, and the letter from Durley Dene, be false? When he came to think of it, Mr. Potter marvelled that he had not discovered this probability before. Why were Laurence Carrington and Miss Scott so apparently intimate? Was it not possible that they might be engaged—or even married? In which case it would be to their mutual advantage were the Squire dead, since then his money would naturally come to them.
"Eureka," cried the man from Burton's, who was proud of his knowledge of half a dozen Greek and Latin words, "I hold in my hand the key to the mystery!"