Ervil Lebaron, Death Toll: at least 15, possibly as many as 40. If you ever watched "Big Love", you'll get the basics of what this guy's deal was. Lebaron was the leader of a breakaway Mormon Polygamist sect (he would eventually have 13 wives, several of whom he married when they were underage). He wasn't originally meant to be the "prophet" of this church, however; that role was supposed to go to his older brother. But Ervil arranged to have him murdered, and he would later try to kill his younger brother (who was running a breakaway sect) as well as the leaders of various other Mormon Polygamist groups who refused to recognize his authority as "prophet". He also arranged the death of various members of his own sect when they defied him or attempted to leave the cult. He may even have killed his own teenage daughter when she tried to escape his church, she was pregnant at the time of her death. Ervil had been in hiding in Mexico but he was eventually extradited and sentenced to life in prison, where he died after less than a year. Two days after he died, his younger brother (the one he'd been trying to kill) died in a mysterious automobile accident; many suspect Ervil had arranged the 'accident' for beyond-the-grave revenge. He had also written a 'hit list' while in prison which he smuggled out in the guise of a religious tract to some of his followers. For up to a decade after LeBaron's death, people alleged to be on that list were murdered or died in mysterious circumstances; at least 4 deaths (including that of an 8 year old girl) were confirmed to have been carried out by followers of Ervil on his death-bed orders.