I read the book DOWN THE GREAT UNKNOWN: JOHN WESLEY POWELL'S 1869 JOURNEY OF DISCOVERY & TRAGEDY by Edward Dolnick (Perennial Books), 2001. Powell, of course, was the one-armed Civil War vet who became the first known white man/white party to venture down the Green/Colorado River thru the Grand Canyon.
Shortly before finishing the trip, three of his party ventured out on foot into Utah Territory...never to be heard from again other than the Mormon leaders trying to pin the deaths of the three men on Indians. [a common pattern by Mormons]
On pp. 283-285, Dolnick cites an amateur historian & former dean of the college of science @ So. Utah Univ. (Wesley Larsen) re: a letter Larsen found in 1980 in a trunk belonging to the John Steele family.
Steele was a judge and a militia officer & father of the first white child born in Utah territory. The letter was written to Steele from William Leany. Both were devout Mormons.
Book mentions Leany had run afoul of the Mormon church by giving an emigrant a meal & roof & veggies.
Book excerpt: "Leany's fellow Mormons charged him with giving 'aid and comfort to the enemy.' To teach him a lesson, someone clubbed him over the head, fracturing his skull and leaving him for dead. Leany survived. By 1883, he and Steele were old men. Steele evidently suggested to his good friend Leany that the time had come for them both to repent of their sins. Leany wanted no part of it. The church had blood on its hands, but he had nothing to repent. Like an Old Testament preacher, Leany thundered that 'thieving whoredom murder & Suicide & like abominations' reigned in the land. Then came the sentence that, a century later, electrified Wes Larsen: 'You are far from ignorant of those deeds of blood from the day the picket fence was broken on my head to the day those three were murdered in our ward & the murderer killed to stop the shedding of more blood.'...Larsen...embarked on a frenzied round of detective work. The reference to 'our ward,' a local Mormon district run by a bishop, was the first clue. Leany and Steele had lived in the same ward only once through the years, in 1869. And in that same fateful year, Larsen found, only one trio of men...had been reported missing or killed in southern Utah."
"Further, Larsen learned, only weeks before the Powell expedition reached Separation Rapid, Brigham Young had traveled throughout the region warning the faithful that the long-threatened invasion of Utah by Gentiles was imminent. When 'war' came, Young warned his listeners, blood would rise 'to their knees and even to their waist and to their horses' bridle bits.' The Mormon leader ordered sentries posted at all the passes leading into southern Utah. Then, at the worst possible moment, three white strangers wandered into no-man's-land spouting a cock-and-bull story about their trip down a river that everyone knew was impassable. The three men were dragged off and executed as spies, Larsen speculates, and the news of the unsanctioned executions triumphantly telegraphed to Salt Lake City..."
"In Larsen's scenario, the next step was an exact replay of the Mormon response to the 120 killings at Mountain Meadows. First came cover-up...then a vow of silence on the part of those who knew the truth, and finally a finger of blame pinning the crime on the nearest Indians."
Yup...that indeed was the Mormon M.O. of the period -- pinning crimes on Native Americans...some of whom worked with Lds in engaging in murder in other cases (like the MMM and the Gunnison party massacres)