In the Torah, where the need for sanctuary cities is being established, a hypothetical situation is described where a bloke is swinging an axe, and the axe head flies off and kills another bloke. The dead man's brother is designated "the avenger" and pursues the original guy in order to kill him for being responsible for the death. He is allowed to do so, if the original guy doesn't make it to a sanctuary city. If both victim and the person who "manslaughtered" him are dead, then there are not two or three witnesses to establish the avenger's story, yet the avenger's testimony is accepted.
Yet WT still insists on two witnesses in a CSA case. 🙄🤢