An event was widely talked about in the town of Alès in Winter 1323. Gui de Corvo, a burgher who died eight days before, came back to haunt his own house and terrify his widow. She first called the consuls, then the Dominican Prior for help. A delegation led by the Prior Jean Gobi, followed by the town notables went to the house. A two-night questioning of this spirit is said to have been transcribed by a notary. This text and its successive developments raise the question of the nature of this voice. How did the Prior condition the audience into believing that it was really the spirit's voice? How did he make this voice answer his questions? What message was it supposed to deliver to the living? How did this kind of text contribute to promote the purgatory souls’ cult in the last centuries of the Middle Ages?