Not much to say about it in a particularly verbose way. Back when the Mormons were in Missouri he took a couple bounties that some nearby towns put out on the Mormon men in general, so he befriended some of the Mormons pretending to be a hunter from Arkansas and then led them to the woods and slit their throats one by one. He basically did this because he was bored and there was a lull in work for his lumber and crops, the pawning off their shit was just a bit of extra money.

Don't know if anything was ever written about it, pretty sure this happened before Missouri declared open season the the Mormons and I think the bounties were technically illegal. Who knows maybe the Mormons wrote about it but it's nothing fancy.

Edit: he didn't actually slit their throats, I've been playing a high casualty MGS2 run because reasons and the imagery is stuck in my head. He shot them in the back.