Wikipedia
Matonabbee (–1782) was a Chipewyan hunter and leader. He traveled with Chief Akaitcho's older brother, Keskarrah. After his father died, Matonabbee spent some time living at Fort Prince of Wales where he learned to speak English.
He acted as a guide for Samuel Hearne during his exploration from 1770 to 1772. On July 14, 1771, on Arctic overland journey, he, his followers, and " Copper Indians" who had joined them at Clowey, massacred a group of over 20 unsuspecting Inuit ("Esquimaux"); this would be known as the Bloody Falls Massacre.
After the death of many Chipewyans during a smallpox epidemic of 1782 and the defeat of Fort Prince of Wales by the French, Matonabbee became depressed after the destruction of the Churchill Factory 1782, which had been the primary source of his fortune and fame. He had been the main middleman between the various tribes of the Cree and the Hudson's Bay Company. He then committed suicide by hanging himself, thus being the earliest record of a Northern Indian to kill himself.