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 on September 20th. The autopsy determined the cause of death was hypothermia.
O’Neill, from Chimacum, Washington, along with his half-brother, 74-year-old Kim Crumbo, from Ogden, Utah, were reported overdue by a family member September 19th from their four-night backcountry trip to Shoshone Lake.
Search and recovery efforts continue at the lake in efforts to locate Crumbo. Crews from the National Park Service’s Submerged Resources Center are using sonar equipment to detect clues in the water.
Park crews also continue to search for Crumbo by foot and boat, with assistance from Grand Teton National Park’s interagency helicopter and dog teams from Western Montana Search Dogs. These recovery efforts will continue for the next several days as conditions permit. The incident remains under investigation.
The public is asked to provide any information they may that could help investigators piece together a timeline of events, or by reporting what they may have seen or not seen on their own visit to Shoshone Lake between September 12th and 19th. That information may be contributed by calling 307-344-2428 or emailing yell_tip@nps.gov.
- Curtis Canyon Ambassadors Report Close Calls with Unsafe Campfires - August 6, 2025
- Pet Goldfish Found Swimming in May Park Pond - August 5, 2025
- Fire Danger Elevated to Very High for Teton Area - July 30, 2025
