GRAND CANYON, Ariz. (AP) — The National Park Service and local medical examiner are investigating the death of a 65-year-old hiker at Grand Canyon National Park who was found unresponsive on the popular Bright Angel Trail, the agency said Friday.

The agency identified the victim as James Handschy, of Oracle, Arizona. Park rangers pronounced him dead at the scene on Thursday.

Emergency officials received an SOS from a personal locator beacon at about 1:30 p.m. Thursday on the trail about 1.5 mile (2.4 kilometers) north of Havasupai Gardens, the agency said in a statement Friday. One rescuer responded on foot immediately and search and rescue personnel followed by helicopter soon after.

Handschy had been attempting to hike from the South Rim of the canyon to the Colorado River at the bottom of the canyon and back, the agency said, a distance of about 18 miles (29 kilometers) roundtrip.

The service is investigating the incident in coordination with the Coconino County Medical Examiner. No other information has been released.