News From SheridanMedia.com An autopsy has been completed on 67-year-old Mark O’Neill whose body was found on the east shore of Shoshone Lake in Yellowstone National Park Monday, Sept. 20. The autopsy determined the cause of death of O’Neill was exposure (hypothermia). O’Neill, from Chimacum, Washington, along with his brother, 74-year-old Kim Crumbo,