But Grandier gained the enmity of cardinal Richelieu after a public verbal attack against him. Richelieu ordered a new trial, with a "special" envoy, Jean de Laubardemont, a relative of the Mother Superior of the convent of Loudun. Grandier was arrested again at Angers, and the possibility of appealing to the Parlement of Paris was denied to him. Interrogated for a second time, the nuns (including the Mother Superior, Jeanne des Anges) did not renew their accusations, but the sentence had been passed before the second trial.

The judges (the clerics de Laubardemont, Lactance, Surin and Tranquille), after torturing the priest presented fake acts signed by Grandier and several demons as a "proof" that he had made a diabolical pact. One of the acts was written in Latin and appeared to be signed by Grandier; another was almost illegible, had many strange symbols, and was "signed" by several demons with their seals, and by Satan himself clearly written "Satanas". It is unknown if Grandier wrote the acts under torment or if they were a falsification; more, it is unknown whether Grandier's signature was his or forged.