During his time as bishop he was tried for embezzlement and – thinking he had lost his case – he decided to poison the pope. He enlisted Pons de Vassal and Isar d’Escodata, both members of the papal court, and procured poisons and wax figurines to bewitch the pope. He first tested the bewitchment against the pope's nephew Jacques de Via. Three wax figurines of the pope, Bertrand du Pouget and Gaucelme de Jean were hidden in loaves and given to messengers to carry into the episcopal palace. However, the messengers' strange behaviour drew the attention of the papal guards, who discovered the figurines. On 23 March 1317 Géraud and everyone else implicated in the plot were arrested. Influential figures from south-west France gravitated towards Géraud's entourage, including Gaillard de Preyssac, Arnaud de Pellegrue and the viscount of Bruniquel. Questioning began on 22 April at the château de Noves and on 5 May the pope commissioned Pierre des Prés and Arnaud de Capdenac to continue the enquiry. The suspects were questioned in secret, meaning the names of major figures implicated in the plot were not revealed. The plot quickly unravelled, with Géraud admitting everything without being tortured and the pope praising des Près's "prudence, faithfulness and experience". During the questioning Jacques de Via died. On 21 August the pope personally questioned Géraud, who nine days later was found guilty of witchcraft, sacrilege and the murder of Jacques de Via. He was dismissed from his bishopric, handed over to the secular arm and burned at the stake in front of the episcopal palace in Avignon. de Preyssac also lost his diocese, but de Pellegrue went unpunished. 1317 also saw the pope issue a papal bull expanding inquisitors' rights when investigating witchcraft and sorcery, followed by another in August 1326 entitled Super illius specula which made sorcery practically equivalent to heresy. This campaign against sorcery was continued by John's successors from pope Benedict XII to Antipope Alexander V. At the pope's request Pierre des Prés also presided over the trials of Géraud's accomplices, most notably those of Pierre de Saleilles in September 1322 and of Bernard Gasc on 26 November 1322
