Believing their promises, Sully thought that the delivery of the arms would solve all the difficulties, so on his advice the agent turned them over along with the annuities, the Indians this time condescendingly accepting.
This issue of arms and ammunition was a fatal mistake; Indian diplomacy had overreached Sully's experience, and even while the delivery was in progress a party of warriors had already begun a raid of murder and rapine, which for acts of devilish cruelty perhaps has no parallel in savage warfare.

The party consisted of about two hundred Cheyennes and a few Arapahoes, with twenty Sioux who had been visiting their friends, the Cheyennes.

As near as could be ascertained, they organized and left their camps along Pawnee Creek about the 3d of August.

Traveling northeast, they skirted around Fort Harker, and made their first appearance among the settlers in the Saline Valley, about thirty miles north of that post.

Professing friendship and asking food at the farm-houses, they saw the unsuspecting occupants comply by giving all they could spare from their scanty stores.