I will have to go through my notes on the subject to see what I can find on Louis Deville. My recollection concerning him comes from some research a friend of mine did back in the late 1970s and early 1980s and then shared with me.
Jayhawkers were bands of men who either opposed the Confederate war effort or were simply bandits. In some cases, these groups did both. People who became Jayhawkers were Unionists, draft dodgers, deserters, and simply bad men. A few had been involved in illegal activities prior to the war, particularly in southwest Louisiana. Some Jayhawkers eventually joined the Union army or served as scouts for it during the two invasions of the Red River Valley. Confederate forces occasionally conducted campaigns against the Jayhawkers but never completely rid the state of them. Ill feelings lingered into the Reconstruction period.