“His methods are irregular, no doubt, like my own. The irregulars are useful sometimes, you know. You, for example, with your compulsory warning about whatever he said being used against him, could never have bluffed this rascal into what is virtually a confession.”

“Perhaps not. But we get there all the same, Mr. Holmes. Don’t imagine that we had not formed our own views of this case, and that we would not have laid our hands on our man. You will excuse us for feeling sore when you jump in with methods which we cannot use, and so rob us of the credit.”

“There shall be no such robbery, MacKinnon. I assure you that I efface myself from now onward, and as to Barker, he has done nothing save what I told him.”

The inspector seemed considerably relieved.

“That is very handsome of you, Mr. Holmes. Praise or blame can matter little to you, but it is very different to us when the newspapers begin to ask questions.”

“Quite so. But they are pretty sure to ask questions anyhow, so it would be as well to have answers. What will you say, for example, when the intelligent and enterprising reporter asks you what the exact points were which aroused your suspicion, and finally gave you a certain conviction as to the real facts?”

The inspector looked puzzled.

“We puzzled don’t seem to have got any real facts yet, Mr. Holmes. You say that the prisoner, in the presence of three witnesses, practically confessed by trying to commit suicide, that he had murdered his wife and her lover. What other facts have you?”

“Have you arranged for a search?”

“There are three constables on their way.”

“Then you will soon get the clearest fact of all. The bodies cannot be far away. Try the cellars and the garden. It should not take long to dig up the likely places. This house is older than the water-pipes. There must be a disused well somewhere. Try your luck there.”

“But how did you know of it, and how was it done?”

“I’ll show you first how it was done, and then I will give the explanation which is due to you, and even more to my longsuffering friend here, who has been invaluable throughout. But, first, I would give you an insight into this man’s mentality. It is a very unusual one — so much so that I think his destination is more likely to be Broadmoor than the scaffold. He has, to a high degree, the sort of mind which one associates with the mediaeval Italian nature rather than with the modern Briton. He was a miserable miser who made his wife so wretched by his niggardly ways that she was a ready prey for any adventurer. Such a one came upon the scene in the person of this chess-playing doctor. Amberley excelled at chess — one mark, Watson, of a scheming mind. Like all misers, he was a jealous man, and his jealousy became a frantic mania. Rightly or wrongly, he suspected an intrigue. He determined to have his revenge, and he planned it with diabolical cleverness. Come here!”

"The house in the Square Lamartine is occupied by Prasville's men."

"Don't worry, Sebastiani. I shall get in. If they don't open the door, there's always the window. And, if the window won't open, I shall arrange with one of Prasville's men. It's a question of money, that's all. And, thank goodness, I shan't be short of that, henceforth! Good-night, Daubrecq."

He went out, accompanied by Sebastiani, and the heavy door closed after them.

Lupin at once effected his retreat, in accordance with a plan which he had worked out during this scene.

The plan was sunple enough: to scramble, by means of his rope, to the bottom of the cliff, take his friends with him, jump into the motor-car and attack d'Albufex and Sebastiani on the deserted road that leads to Aumale Station. There could be no doubt about the issue of the contest. With d'Albufex and Sebastiani prisoners; it would be an easy matter to make one of them speak. D'Albufex had shown him how to set about it; and Clarisse Mergy would be inflexible where it was a question of saving her son.

He took the rope with which he had provided himself and groped about to find a jagged piece of rock round which to pass it, so as to leave two equal lengths hanging, by which he could let himself down. But, when he found what he wanted, instead of acting swiftly - for the business was urgent - he stood motionless, thinking. His scheme failed to satisfy him at the last moment.

"It's absurd, what I'm proposing," he said to himself. "Absurd and illogical. How can I tell that d'Albufex and Sebastiani will not escape me? How can I even tell that, once they are in my power, they will speak? No, I shall stay. There are better things to try... much better things. It's not those two I must be at, but Daubrecq. He's done for; he has not a kick left in him. If he has told the marquis his secret, there is no reason why he shouldn't tell it to Clarisse and me, when we employ the same methods. That's settled! We'll kidnap the Daubrecq bird." And he continued, "Besides, what do I risk? If the scheme miscarries, Clarisse and I will rush off to Paris and, together with Prasville, organize a careful watch in the Square Lamartine to prevent d'Albufex from benefiting by Daubrecq's revelations. The great thing is for Prasville to be warned of the danger. He shall be."

The church-clock in a neighbouring village struck twelve. That gave Lupin six or seven hours to put his new plan into execution. He set to work forthwith.

When moving away from the embrasure which had the window at the bottom of it, he had come upon a clump of small shrubs in one of the hollows of the cliff. He cut away a dozen of these, with his knife, and whittled them all down to the same size. Then he cut off two equal lengths from his rope. These were the uprights of the ladder. He fastened the twelve little sticks between the uprights and thus contrived a rope-ladder about six yards long.

When he returned to this post, there was only one of the three sons beside Daubrecq's bed in the torture-chamber. He was smoking his pipe by the lamp. Daubrecq was asleep.