In September 1752, Serra filed a report to the Spanish Inquisition in Mexico City from Jalpan, on "evidences of witchcraft in the Sierra Gorda missions." He denounced several Christian non-Indians who lived in and around the mission for "the most detestable and horrible crimes of sorcery, witchcraft and devil worship. ... If it is necessary to specify one of the persons guilty of such crimes, I accuse by name a certain Melchora de los Reyes Acosta, a married mulattress, an inhabitant of the said mission. . ... In these last days a certain Cayetana, a very clever Mexican woman of said mission, married to one Pérez, a mulatto, has confessed—she, being observed and accused of similar crimes, having been held under arrest by us for some days past—that in the mission there is a large congregation of non-Indians, although some Indians also join them, and that these persons, ... flying through the air at night, are in the habit of meeting in a cave on a hill near a ranch called El Saucillo, in the center of said missions, where they worship and make sacrifice to the demons who appear visibly there in the guise of young goats and various other things of that nature. ... If such evil is not attacked, the horrible corruption will spread among these poor neophytes who are in our charge."