This testimony was given by Edward Wynkoop, a major in the 1st Colorado Cavalry, who was called before the military commission investigating the massacre of Cheyenne Indians at Sand Creek, Colorado, in 1864. Wynkoop gives a detailed description of his personal interactions with the Cheyenne, Indian depredations allegedly committed in the area, and the events that occurred along Sand Creek. Although this commission was not a criminal trial, the format of taking witness's testimony was similar—Colonel Chivington, commander of the 1st Colorado, was allowed to cross-examine the witnesses called by the commission. The testimony is part of a larger report containing evidence obtained at this hearing, titled Report of the Secretary of War, Communicating, In compliance with a resolution of the Senate of February 4, 1867, a copy of the evidence taken at Denver and Fort Lyon, Colorado Territory, by a military commission, ordered to inquire into the Sand Creek massacre, November, 1864. This report also includes transcriptions of documents called as evidence.