The article is an interesting take on the time period

For one example, I think Porter Rockwell is less considered a lawman, and more of a hitman or enforcer. He's suspected of having a body count somewhere in the 150 range

edit:

It also completely leaves out the entire Mountain Meadows Massacre incident, where Mormons slaughtered around 120 men women and children in a wagon train headed to California in September of 1857

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

For a little bonus Utah trivia, the only person actually punished for the Massacre is current Senator Mike Lee's great-great-grandfather.