Killin' Jim Miller et al.

Left to right: Jim Miller, Joe Allen, Berry Burrell, and Jesse West, hanged by vigilantes in Ada, Oklahoma, April 19, 1909.

Killin' Jim Miller didn't drink or smoke. He just liked killing people. He was alternately a murderer, a sheriff, and a hired killer. But he was caught, and when it looked like he might find a way to get off, good citizens took the law into their own hands. The other three lynched with Miller had hired him to dispose of a rival of theirs. (Some info from here and here.)