With the keenest anticipation he awaited the time when Mme. de Combray's letters to Bonnœil and "Tourlour" should be handed to him. He had to be patient till next day, and this first letter told nothing; the Marquise gave her accomplices a sketch of her examination, and did it so artfully that Licquet suspected her of having known that the letter was to pass through his hands. The same day the concierge gave him another letter as insignificant as the first, which, however, ended with this sentence, whose perusal puzzled Licquet: "Do you not know that Tourlour's brother has burnt the muslin fichu?"

"Tourlour's brother"—that was d'Aché. Had he recently returned to Tournebut? Was he still there? Another letter, given to the gaoler by Bonnœil, answered these questions affirmatively. It was addressed to a man of business named Legrand in the Rue Cauchoise, and ran thus: "I implore you to start at once for Tournebut without telling any one of the object of your journey; go to Grosmenil (the little château), see the woman Bachelet, and burn everything she may have that seems suspicious; you will do us a great service. Return this letter to me. Tell Soyer that if any one asks if M. d'Aché has returned, it is two years since he was seen at Tournebut."

That same evening the order for Soyer's arrest was sent to Gaillon, and twelve hours later he also was in the Conciergerie at Rouen. This did not prevent Bonnœil's writing to him the next day, Licquet, as may be imagined, not having informed the prisoners of his arrest.

"I beg you, my dear Soyer, to look in the two or three desks in my mother's room, and see if you cannot find anything that could compromise her, above all any of M. Delorières' (d'Aché's) writing. Destroy it all. If you are asked how long it is since M. Delorières was at Tournebut, say he has not been there for nearly two years. Tell this to Collin, to Catin, and to the yard girl...."

Licquet carefully copied these letters and then sent them to their destination, hoping that the answers would give him some light. In his frequent visits to the prisoners he dared not venture on the slightest allusion to the confidences they exchanged, for fear that they might suspect the fidelity of their messenger, and refuse his help. Thus, many points remained obscure to the detective. The next letter from Bonnœil to Soyer contained this sentence: "Put the small curtains on the window of the place where I told you to bury the nail...." We can imagine Licquet with his head in his hands trying to solve this enigma. The muslin fichu, the little curtains, the nail—was this a cipher decided on in advance between the prisoners? And all these precautions seemed to be taken for the mysterious d'Aché whose safety seemed to be their sole desire. A word from Mme. de Combray to Bonnœil leaves no doubt as to the conspirator's recent sojourn at Tournebut: "I wish Mme. K.... to go to my house and see with So ... if Delor ... has not left some paper in the oil-cloth of the little room near the room where the cooks slept. Let him look everywhere and burn everything." This time the information seemed so sure that Licquet started for Tournebut, which had been occupied by gendarmes for a fortnight; he took Soyer to guide him, and the commissary of police, Legendre, to make a report of the search.

They arrived at Tournebut on the morning of September 5th. Licquet, who was much exhilarated by this hunt for conspirators, must have felt a singular emotion on approaching the mysterious mansion, object of all his thoughts. He took it all in at a glance, he was struck by the isolation of the château, away from the road below the woods; he found that it could be entered at twenty different places, without one's being seen. He sent away the servants, posted a gendarme at each door, and conducted by Soyer, entered the apartments.

First he went to the brick wing built by de Marillac, where was a vast chamber occupied by Bonnœil and leading to the great hall, astoundingly high and solemn in spite of its dilapidation, with a brick floor, a ceiling with great beams, and immense windows looking over the terrace towards the Seine. By a double door with monumental ironwork, set in a wall as thick as a bastille, Mme. de Combray's apartments were reached, the first room wainscoted, then a boudoir, next a small room hidden by a staircase, and communicating with a lot of other small, low rooms. A long passage, lighted by three windows opening on the terrace, led, leaving the Marquise's bedchamber on the right, to the most ancient part of the château the front of which had been recently restored. Having crossed the landing of the steps leading to the garden, one reached the salon; then the dining-room, where there was a stone staircase leading to the first floor. On this were a long passage and three chambers looking out on the valley of the Seine, and a lot of small rooms that were not used. All the rest was lofts, where the framework of the roofs crossed. When a door was opened, frightened bats flapped their wings with a great noise in the darkness of this forest of enormous, worm-eaten beams. In fact, everything looked very simple; there was no sign whatever of a hiding-place. The furniture was opened, the walls sounded, and the panels examined without finding any hollow place. It was now Soyer's turn to appear. Whether he feared for himself, or whether Licquet had made him understand that denial was useless, Mme. de Combray's confidential man consented to guide the detectives. He took a bunch of keys and followed by Licquet and Legendre, went up to a little room under the roof of a narrow building next to Marillac's wing. This room had only one window, on the north, with a bit of green stuff for a curtain; its only furniture was a miserable wooden bed drawn into the middle of the room. Licquet and the commissary examined the partitions and had them sounded. Soyer allowed them to rummage in all the corners, then, when they had given up all idea of finding anything themselves, he went up to the bed, put his hand under the mattress and removed a nail. They immediately heard the fall of a weight behind the wall, which opened, disclosing a chamber large enough to hold fifteen persons. In it were a wooden bench, a large chafing-dish, silver candlesticks, a trunk full of papers and letters, two packets of hair of different colours, and some treatises on games. They seized among other things, the funeral oration of the Duc d'Enghien, copied by Placide, and the passport d'Aché had obtained at Rouen in 1803, which was signed by Licquet. When they had put everything in a bag and closed the partition, when they had sufficiently admired the mechanism which left no crack or opening visible, Soyer, still followed by two policemen, went over the whole château, climbed to the loft, and stopped at last in a little room at the end of the building. It was full of soiled linen hung on ropes; a thick beam was fixed almost level with the ground, the whole length of the wall embellished with shelves supported by brackets. Soyer thrust his hand into a small, worm-eaten hole in the beam, and drawing out a piece of iron, fitted it on a nail that seemed to be driven into one of the brackets. Instantly the shelves folded up, a door opened in the wall, and they entered a room large enough to hold fifty people with ease. A window—impossible to discover from the outside—opened on the roof of the chapel, and gave light and air to this apartment; it contained only a large wardrobe, in which were an earthen dish and an altar stone.

And so this old manor-house, with its venerable and homelike air, was arranged as a resort for brigands, and an arsenal and retreat for a little army of conspirators. For Soyer also revealed the secrets of the oubliettes of the little château, whose unfurnished rooms could shelter a considerable garrison; they only found there three trunks full of silver, marked with so many different arms that Licquet believed it must have come from the many thefts perpetrated during the last fifteen years in the neighbourhood. On examination it proved to be nothing of the sort, but that all these different pieces of silver bore the arms of branches of the families of Brunelle and Combray; but even though he was obliged to withdraw his first supposition, Licquet was firm in attributing to the owners of Tournebut all the misdeeds that had been committed in the region since the Directory. These perfect hiding-places, this château on the banks of the river, in the woods between two roads, like the rocky nests in which the robber-chiefs of the middle ages fortified themselves, explained so well the attacks on the coaches, the bands of brigands who disappeared suddenly, and remained undiscoverable, that the detective gave free rein to his imagination. He persuaded himself that d'Aché was there, buried in some hollow wall of which even Soyer had not the secret, and as the only hope, in this event, was to starve him out, Licquet sent all of Mme. de Combray's servants away, and left a handful of soldiers in the château, the keys of which, as well as the administration of the property, he left in the hands of the mayor of Aubevoye.

His first thought on returning to Rouen was for his prisoners. They had continued to correspond during his absence, and copies of all their letters were faithfully delivered to him; but they seemed to have told each other all they had that was interesting to tell, and the correspondence threatened to become monotonous. The imagination of the detective found a way of reawakening the interest. One evening, when every one was asleep in the prison, Licquet gave the gaoler orders to open several doors hastily, to push bolts, and walk about noisily in the corridors, and when, next day, Mme. de Combray enquired the cause of all this hubbub, she was easily induced to believe that Lefebre had been arrested at Falaise and imprisoned during the night. An hour later the concierge, with a great show of secrecy, gave the Marquise a note written by Licquet, in which "Lefebre" informed her of his arrest, and said that he had disguised his writing as an act of prudence. The stratagem was entirely successful. Mme. de Combray answered, and her letter was immediately given to Licquet, who, awaiting some definite information, was astonished to find himself confronted with a fresh mystery. "Let me know," said the Marquise, "how the horse went back; that no one saw it anywhere."