[5][6] At the Camp Weld Council of September 28, 1864, Evans and Chivington met with five chiefs, including Black Kettle of the Cheyenne and White Antelope of the Arapaho.

They had been brought to Denver to parlay for peace under military escort by Major Edward W. Wynkoop, commander of Fort Lyon.

The chiefs agreed to peacefully settle their people on the reservation on Big Sandy Creek about 40 miles northwest of Fort Lyon.

Although Black Kettle had flown an American flag on his tipi to signal peace (as directed by Wynkoop), the volunteers killed indiscriminately.

The hearings were widely covered, leading to national shock and outrage about the brutality of the attack and the betrayal of promises made to the Cheyenne and Arapaho.

Because the Native Americans believed the Cheyenne had been targeted by the US, major Sioux and Arapaho bands allied with them from 1865 on to attack the Vehos (whites) and try to drive emigrant settlers out of their lands.