So astounded were _Monsieur le Duc_ and the majority of his counsellors at such tactics on the part of their enemies that, for a moment, they were at a loss how to proceed. Madame de Prie, however, retained her presence of mind and insisted on prompt and energetic action, pointing out that it was now a case of war to the knife in the most literal sense of the expression, and that, if they did not hasten to crush their adversaries, they would certainly be crushed themselves. It was ultimately decided to follow her counsels. The Chevalier de Belle-Isle was forthwith arrested and conveyed to the Château of Vincennes. On 5 March, Du Val, commandant of the mounted police, furnished with a _lettre de cachet_, proceeded to Doué, where he arrested the late Minister for War and conducted him to Paris and the Bastille. The same night, the police surrounded the hôtel of the Comte de Belle-Isle, with orders to apprehend both the count and his friend the Marquis de Conches, who was staying with him. They secured Belle-Isle and escorted him to the Bastille, whither his younger brother had been transferred a few hours previously; but Conches disguised himself and succeeded in effecting his escape by a secret door. He did not, however, remain long at large, for he was captured the following day at a house in the Rue Tavannes, where he had taken refuge, and sent to join his friends in misfortune. Numerous other arrests followed, including that of Moreau de Séchelles, a high official at the Ministry of War and an intimate friend of Le Blanc. But what aroused the most sensation was the apprehension of a man named Lempereur and his two sons and of two brothers called Mestre, sons of a soldier in the Cent-Suisses. This Lempereur, who lived in an isolated house near the wood of Rueil, had formerly been a gardener at the Château of La Jonchère, and he was suspected of having murdered Sandrier, with the assistance of his sons and the Mestres. He was also suspected of being concerned in another crime, which the police believed to be closely connected with the first. One evening in September, 1722--that is to say, about five months after the discovery of Sandrier’s body--a carter in the employ of the tenant of La Malmaison, a farm upon the La Jonchère estate, afterwards celebrated as the residence of the Empress Josephine, had been murdered close to his master’s door. As nothing upon him had been touched, and he was not known to have any private enemies, the inference was that he had been in possession of certain facts concerning the death of Sandrier which had made his removal necessary to the safety of the assassins.