You ought to read Langford's book, vigilante Days and Ways.
"The Young Alaskans on the Missouri"
Emerson Hough
Since the first vigilante days there has been no sound in all the West so dreaded as that deep-throated murmur of angry, honest men.
"Black Jack"
Max Brand
But it is very fearful to contemplate that there may still exist persons in the world filled with a morbid craving for human blood, which is ready to impel them to commit the most horrible atrocities, should they escape the vigilante of their guards, or break the bars of the madhouse which restrains them.
"The Book of Were-Wolves"
Sabine Baring-Gould