I Wanna...Smonk by Tom Franklin

It's 1911 and the townsfolk of Old Texas, Alabama, have had enough. Every Saturday night for a year, E. O. Smonk has been destroying property, killing livestock, seducing women, cheating and beating men, all from behind the twin barrels of his Winchester 45-70 caliber over-and-under rifle. Syphilitic, consumptive, gouty, and goitered—an expert with explosives and knives—Smonk hates horses, goats, and the Irish, and it's high time he was stopped. But capturing old Smonk won't be easy—and putting him on trial could have shocking and disastrous consequences, considering the terrible secret the citizens of Old Texas are hiding. 

-- Smonk by Tom Franklin

(I seem to recall that this was a favorite of Alden Bell who wrote The Reapers are the Angels, one of my favorite books of 2010.)