Maggie, I could not find a Fred Riddle that lived on the Sioux Resv in the 1900's. The Riddle's belong to the Eastern Band of Cherokee (Echota's) of NC, TN, AL and GA. A William Riddle (Indian Countryman) is found working as an interpreter at the Choctaw Trading House in Alabama in 1808. Others were caught up in the Trail of Tears. The Riddle's were used as interpreters so this might be a clue to your Fred. Carol