There was an organization that existed in Utah after the Danites were disbanded. They were known as the Destroying Angels. The Mormons did kill people who were no threat to them in southern Utah. This was the Mountain Meadow Massacre on 11 September 1957. They killed over 100 men, women, and children on a wagon train from Arkansas. The only ones spared were children younger than 7. Even children as young as 9 were killed after the party was promised safe passage after turning over their weapons. Those left alive were given to Mormons in Utah to raise but eventually returned to their families back East. This was "The Crime of the Century" in the 1800's. There are some great books and many websites about it.
Review of The Avenging Angel
