CODY, Wyoming — A missing hiker was found dead in Yellowstone National Park on Friday, prompting authorities to close the area around a popular trail while they investigate the cause, officials said.

The man, who worked in the park, had been reported missing by co-workers Thursday morning. He was found by rangers at around noon in the vicinity of the Elephant Back Loop Trail in the Lake Village area where he had been hiking.

A conclusive cause of death has yet to be determined, Yellowstone spokeswoman Julena Campbell said, but she said rangers investigating the incident had found signs of grizzly bear activity in the area, bear scat, fur and patches of depressed grass, known as day beds, where one or more bears may have rested during the day.

Park officials have not released the hiker’s name or provided additional details about the incident pending notification of family members, though they did say he was from Montana.

The area around Elephant Back Loop Trail has been closed to hikers while the investigation continues.

Fatal bear attacks are uncommon among the 3.5 million annual visitors who roam across Yellowstone’s 2.2 million acres. But park officials say they continually are working to educate the public about the dangers posed by grizzlies and other wildlife.

Two people were killed in separate bear attacks in Yellowstone in 2012, and four people have been injured by bison so far this year.

Park visitation for 2015 is on a record pace, up 20 percent over last year.

Officials remind hikers to stay on designated trails, leave an itinerary with others, hike in groups of three or more, make noise on the trail and carry bear spray.