There was certainly bushwhacker activity in Morgan County and adjacent Benton County during the war years. Volume II of Morgan County History relates of Herman Frisch, operator of Boyler's Mill in west Buffalo Township:

"Bushwhackers came during the Civil War and demanded money from Mr. Frisch. When he refused or wasn't found they set fire to the home. After he gave them what they demanded, the family was allowed to extinguish the flames. They --- stated they would have killed him but they needed a miller to provide some of their food."

Henry Gerlt's legend is also related on his Find-a-Grave site:

http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=16337874