The National Park Service says a missing New Mexico man who is "believed to have attempted travel down the Colorado River with his dog on a wooden raft" has been found dead inside Grand Canyon National Park. 

Thomas Robison, 58, of Santa Fe, was discovered by park rangers in the Colorado River on Friday, according to the NPS.  

The agency previously said on April 21, a champagne 2001 Toyota Tacoma belonging to Robison "was found abandoned at Lee’s Ferry in Glen Canyon National Recreation Area" and that his whereabouts were unknown at the time. 

"It is believed he may have attempted to go down the Colorado River with his dog, who is a Welsh Corgi, on a self-made raft," they said. 

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Thomas Robison and his dog

Thomas Robison of Santa Fe, New Mexico, and his dog. (NPS)

Robison’s body is now being examined by the Coconino County Medical Examiner and the NPS is investigating the incident. The NPS says "initial information" indicates that the body is of Robison. 

The cause of his death is unclear. 

It comes after an Arizona hiker died on a popular Grand Canyon hiking trail in November 2023 in what was the 10th death that year at the national park. 

The NPS identified that hiker as 65-year-old James Handschy of Oracle, Arizona. 

Handschy had set off for a hike from the South Rim to the river and back along the Bright Angel Trail, the agency said, a roundtrip of about 18 miles. 

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Thomas Robison and homemade raft

The homemade raft that Robison, 58, is believed to have set off on in an attempt to travel down the Colorado River, NPS officials say.

In September 2023, another Grand Canyon hiker died while trying to walk rim to rim in one day, officials said. 

Ranjith Varma, 55, of Manassas, Virginia, was attempting to trek from the South to North Rim on Sept. 9 when he became unresponsive along the North Kaibab Trail, approximately one mile south of Cottonwood Campground, the National Park Service said. 

Rangers responded to the emergency call about the hiker in distress and deployed a helicopter with search and rescue personnel, the NPS said. 

Helicopter flying over Grand Canyon

The NPS says Robison's body was found inside Grand Canyon National Park on Friday, May 10. (NPS)

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Bystanders performed CPR until the rangers arrived. 

Fox News’ Stephen Sorace contributed to this report.