Long assumed to have been involved in the infamous Affaire des Poisons, Madame de Montespan has never been conclusively implicated. Gabriel Nicolas de La Reynie, Paris' first Lieutenant General of Police and the chief judge of the court, before whom the famous poisoning cases were brought, heard testimony that placed Madame de Montespan's first visits to the so-called witch Catherine Monvoisin, known as La Voisin, in 1665. According to this testimony, they repeatedly carried out rituals that would create a special potion for the King. The witch and the Madame de Montespan would call on the devil, and pray to him for the King's love. As a way to express her gratitude for her request, they sacrificed a newborn's life by slitting its throat with a knife. Next, the baby's body would be crushed, and the drained blood and mashed bones would be used in the mixture. Louis's food was tainted in this way for almost thirteen years, until the witch was captured after a police investigation where they uncovered the remains of 2,500 infants in La Voisin's garden. Even though no evidence that the garden search ever actually happened are found. In 1666, Madame de Montespan supposedly went so far as to allow a priest, Étienne Guibourg, to perform a black mass over her nude body in a blood-soaked ceremony, which was also said to have included infant sacrifice. Whatever the truth in these allegations, in July 1667, Madame de Montespan became the king's new mistress even though Louise was carrying his child, Louis de Bourbon, comte de Vermandois.