A Study in Scarlet. Sir Arthur Conan Doyle

"Its invisibility, and the mystery which was attached to it, made this organization doubly terrible. It appeared to be omniscient and omnipotent, and yet was neither seen nor heard. The man who held out against the Church vanished away, and none knew whither he had gone or what had befallen him. His wife and his children awaited him at home, but no father ever returned to tell them how he had fared at the hands of his secret judges. A rash word or a hasty act was followed by annihilation, and yet none knew what the nature might be of this terrible power which was suspended over them. No wonder that men went about in fear and trembling, and that even in the heart of the wilderness they dared not whisper the doubts which oppressed them.
At first this vague and terrible power was exercised only upon the recalcitrants who, having embraced the Mormon faith, wished afterwards to pervert or to abandon it. Soon, however, it took a wider range. The supply of adult women was running short, and polygamy without a female population on which to draw was a barren doctrine indeed. Strange rumours began to be bandied about -- rumours of murdered immigrants and rifled camps in regions where Indians had never been seen. Fresh women appeared in the harems of the Elders -- women who pined and wept, and bore upon their faces the traces of an unextinguishable horror."