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Crews search for former Navy SEAL after his brother is found dead in Yellowstone

Authorities found Mark O'Neill, 67, on the east shore of Shoshone Lake, the National Park Service said. A cause of death was not immediately released.
Image: Shoshone Lake in Yellowstone National Park.
Shoshone Lake in Yellowstone National Park.Jacob W. Frank / National Park Service

Rescue crews are continuing their search for a former Navy SEAL after they recovered the body of his brother Monday in Yellowstone National Park, officials said.

Authorities found Mark O'Neill on the east shore of Shoshone Lake, the park's second-largest lake, according to the National Park Service. A cause of death was not immediately released.

O'Neill, 67, of Chimacum, Washington, and Kim Crumbo, 74, of Ogden, Utah — both retired from the park service — were reported missing by a family member Sunday after they failed to return from their four-night backcountry trip, the federal agency said.

"On Sunday, Sept. 19, park crews located a vacant campsite with gear on the south side of Shoshone Lake, as well as a canoe, paddle, PFD and other personal belongings on the east shore of the lake," the NPS said. Crews found the body of O'Neill the next morning.

Authorities continued their search for Crumbo on Tuesday, with 10 crew members on the ground as a helicopter flew above.

In addition to his military service, Crumbo spent two decades working as a river ranger, park ranger and wilderness coordinator in Grand Canyon National Park, The Salt Lake Tribune reported. He was a member of the Potawatomi tribe and a board member of the Rewilding Institute, a conservation program, according to its website.

Crumbo was also a frequent contributor to The Salt Lake Tribune, which reported he was known for "writing letters to the editor about protecting wolves, wild horses and the environment."

The park service said the average year-round temperature at the lake is about 48 degrees Fahrenheit. Survival time is estimated to be only 20 to 30 minutes in water at that temperature.