BOULDER, Colo. (AP) — The Boulder County coroner’s office says a 25-year-old man whose body was found below a popular route up Longs Peak in Rocky Mountain National Park died of hypothermia.

Peter Jeffris, of Broomfield, was found dead about 200 feet below the Keyhole route Nov. 20. His death has been ruled an accident.

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Authorities believe Jeffris set out for the top of the 14,259-foot mountain a few days before. His car was found at the Longs Peak trailhead after he didn’t show up for work.

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Thousands of hikers reach the summit of Longs Peak every year, but some routes require technical climbing skills, especially in wintry weather.

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