Theriault, the leader of the most bizarre and violent cult in Canadian history, often physically abused his followers. Obsessed with anatomy and medicine, Theriault performed crude intestinal surgery on Boislard by slicing open her abdomen and ripping out a piece of intestine with his bare hands. He then ordered another follower to stitch up the wound with a needle and thread. When she died the next day in agonizing pain, he sawed off the top of her head, and then sexually assaulted her. Before burying the woman, he removed a rib, which he wore around his neck.
Apparently, a movie was made based on these events called Savage Messiah. Just added it to my netflix queue.