The sergeant Cluet deposed:  that, observing a lackey to M. d’Aubray, the councillor, to be the man Lachaussee, whom he had seen in the service of Sainte-Croix, he said to the marquise that if her brother knew that Lachaussee had been with Sainte-Croix he would not like it, but that Madame de Brinvilliers exclaimed, “Dear me, don’t tell my brothers; they would give him a thrashing, no doubt, and he may just as well get his wages as any body else.”  He said nothing to the d’Aubrays, though he saw Lachaussee paying daily visits to Sainte-Croix and to the marquise, who was worrying Sainte-Croix to let her have her box, and wanted her bill for two or three thousand pistoles.  Other wise she would have had him assassinated.  She often said that she was very anxious that no one should see the contents of the box; that it was a very important matter, but only concerned herself.  After the box was opened, the witness added, he had told the marquise, that the commissary Picard said to Lachaussee that there were strange things in it; but the lady blushed, and changed the subject.  He asked her if she were not an accomplice.  She said, “What!  I?” but then muttered to herself:  “Lachaussee ought to be sent off to Picardy.”  The witness repeated that she had been after Sainte-Croix along time about the box, and if she had got it she would have had his throat cut.  The witness further said that when he told Briancourt that Lachaussee was taken and would doubtless confess all, Briancourt, speaking of the marquise, remarked, “She is a lost woman.”  That d’Aubray’s daughter had called Briancourt a rogue, but Briancourt had replied that she little knew what obligations she was under to him; that they had wanted to poison both her and the lieutenant’s widow, and he alone had hindered it.  He had heard from Briancourt that the marquise had often said that there are means to get rid of people one dislikes, and they can easily be put an end to in a bowl of soup.

The girl Edme Huet, a woman of Brescia, deposed that Sainte-Croix went to see the marquise every day, and that in a box belonging to that lady she had seen two little packets containing sublimate in powder and in paste:  she recognised these, because she was an apothecary’s daughter.  She added that one day Madame de Brinvilliers, after a dinner party, in a merry mood, said, showing her a little box, “Here is vengeance on one’s enemies:  this box is small, but holds plenty of successsions!” That she gave back the box into her hands, but soon changing from her sprightly mood, she cried, “Good heavens, what have I said?  Tell nobody.”  That Lambert, clerk at the palace, told her he had brought the packets to Madame from Sainte-Croix; that Lachaussee often went to see her; and that she herself, not being paid ten pistoles which the marquise owed her, went to complain to Sainte-Croix, threatening to tell the lieutenant what she had seen; and accordingly the ten pistoles were paid; further, that the marquise and Sainte-Croix always kept poison about them, to make use of, in case of being arrested.