Indian agent George Armstrong reports [Mountain Meadows] massacre to Brigham Young in a letter from Provo.
"Wm. Matthews had reached home, and brought the melancholy intelligence of a large party of emigrants from Missouri, to Cal-being killed by indians. Said they excited their rage, by poisoning a dead ox, which the indians ate, and several of them died immediatly [sic]. That they then pursued the party & killed all, save a few children, and they were taken to Filmore city, and left with the saints."
[Source: Mountain Meadows Massacre timeline, Will Bagley]