Cult Ritual Killings in Ancient Rome.

 The Romans believed that in order to maintain the favored status of the gods, they needed to perform ritual killings. Sacrificial murder was a violation of established Roman law, but ritual killing offered a loophole, such as if it was prescribed by the gods or involved the killing of foreigners and slaves, who were not Roman citizens.

https://www.winterwatch.net/2024/06/cult-ritual-kliings-in-ancient-rome/