In, June 1851, an Indian agent named Thomas Fitzpatrick had sent out runners to the tribes of the plains to meet at Fort Atkinson. Fitzpatrick had the goal in mind to convince the tribes to go to a peace council that was going to take place at Fort Laramie. While at the meeting at Fort Atkinson, the tribes in attendance were able to use the camp while trading with the troops. Lean Bear saw a ring on a white woman's hand, and having a fascination with jewelry, he grabbed her hand to get a better look. Her husband hit Lean Bear with his luggage and insisted that Fitzpatrick give him a beating. This enraged Lean Bear and he, being a young warrior, rode through the Cheyenne camp demanding an assault on the whites. The Cheyennes went to Agent Fitzpatrick and asked for something to make up for this insult. Fitzpatrick refused, but was later approached by the other tribes informing him that the Cheyenne were planning an attack. Upon learning this, Fitzpatrick had the General on location station dragoons near the Cheyenne side of the camp. This worried the Cheyennes. Later the whites presented a blanket prepared for Lean Bear, and the situation was resolved.
In 1857, Chief Lean Bear approached William Bent with concern about attacks on his people by Sumners troops along the Republican River. He then later became one of the principal signers in the Treaty of Fort Wise. While Lean Bear was the leader of a group of Cheyenne who were camped near Ash Creek in Kansas, he and his tribe were massacred by the Colorado miltia in 1864. While Lean Bear and his tribe were holding a buffalo hunt on the Smoky Hill River, he rode down to meet the troops who had just arrived. On his chest, Lean Bear wore with pride his peace medal that he had received on his trip to Washington D.C. in 1862, and in his hand held an official document, signed by President Abraham Lincoln, stating that he was peaceful and friendly with whites. They were unarmed, and Lean Bear approached the militia alone to show his peaceful intentions. The militia, under the command of Lieutenant George Eayre, approached their village. When they did so, Lean Bear and his fellow Cheyenne came forward to greet them. Eayre's troops had been ordered by Colonel John M. Chivington, to kill Indians on sight, and Eayre ordered his men to shoot Lean Bear. Lean Bear was shot off his horse, and was then shot repeatedly by the soldiers as he lay on the ground.
- West, Elliott (1998). The Contested Plains: Indians, Goldseekers, and the Rush to Colorado. Lawrence, KN: University Press of Kansas. p. 284.
- Ricky 182
- "Lean Bear". Axel-jacob.de. Accessed 28 Feb 2006.