The Ant Hill Kids
Even though the preceding entry's circumstance was tragic, what we know now pales in comparison to what Roch "Moses" Thériault perpetrated on his followers. They drifted from community to community before settling in Burnt River, Ontario in 1977. The excommunicated member of the Seventh Day Adventist church recruited his small group of followers on the promise that the world will end in February 1979. Their main interaction with the neighborhood was the sale of baked goods at the neighborhood general store.
The end of the doomsday didn't have any effect on Moses' power. Despite not having a medical education, he developed the bizarre habit of conducting all surgery on his followers, including appendectomies, castrations, and amputations without anesthesia. Before Gabrielle Lavelle staggered away from the compound in 1989 minus a newly amputated limb, his followers were too scared of him to leave. Some of them were also so under his control that they would accept penalties like beating their own legs with sledgehammers. Ultimately, Thériault was detained in 1989, given a life sentence in 1993, and met his own demise at the hands of another prisoner in 2011.