Sept 11, 1857 Mountain Meadows Massacre

The Mormons, dressed as Paiutes so they could blame the Indians, killed between 120-140 men, women and children. They tried to come up with all sorts of reasons, but reading the narrative, it appears it was to steal their livestock and rob the dead.

John D. Lee, an officer for the Mormon Militia ended up with a lot of the cattle and was the only one tried out of the number of men involved.

Here's something interesting. His descendants include Mark and Tom Udall.

https://en.wikipedia.org/wiki/Mountain_Meadows_Massacre