The following is quite helpful and, if anyone can positively identify the Fitzwilliam named in the article as James Fitzwilliam of Ft. Smith, I would greatly appreciate any feedback about his involvement.

http://www.nytimes.com/1864/05/05/news/war-far-west-bushwhackers-carnival-western-arkansas-murders-fights-near.html?pagewanted=all

Hope this helps everyone