Sozomen was a Christian author, who lived in the first half of the fifth century and wrote an Ecclesiastical History. The following story (5.10) may be true, although the remarks about sacred prostitution are probably innuendo. The translator is unknown.
The Virgins of Heliopolis
[5.10.1] The inhabitants of Heliopolis ... were guilty of an act of barbarity which could scarcely be credited, had it not been corroborated by the testimony of those who witnessed it. They stripped the holy virgins, who had never been looked upon by the multitude, of their garments, and exposed them in a state of nudity as a public spectacle and objects of insult. After numerous other inflictions they at last shaved them, ripped them open, and concealed in their viscera the food usually given to pigs; and since the swine could not distinguish, but were impelled by the need of their customary food, they also tore in pieces the human flesh.
[5.10.2] I am convinced that the citizens of Heliopolis perpetrated this barbarity against the holy virgins on account of the prohibition of the ancient custom of yielding up virgins to prostitution with any chance comer before being united in marriage to their betrothed. This custom was prohibited by a law enacted by Constantine, after he had destroyed the temple of Venus at Heliopolis, and erected a church upon its ruins.