As were some regular army regiments. A descendent of a man in the 6th Kansas Cavalry recently sent me copies of some letters the man had written to his parents back in Kansas. Among other things, the man told his parents how they had burned Confederate prisoners (alleged bushwhackers) alive. Lots of similar incidents related in the letters -- don't know why a man would write such things to his parents. The incidents took place in Arkansas and the Indian Territory.