The National Park Service of Yellowstone National Park believe a seasoned hiker who went missing was killed by a grizzly bear.

The man, whose name has not been released at time, was known as an experience hiker and had lived and worked in the park for five seasons, according to The Washing Post.

The man worked for Medcor on a seasonal basis, a company that operates urgent care clinics in the park area. When he did not show up for work on Friday, they found it very unusual, which is when he was reported missing.

The report said that a park ranger found the man already partly consumed about a half-mile from the Elephant Back Loop Trail which is known as a very popular off-trail area where the man and many others were known to frequent.

The official cause of death is still under investigation by officials. But according to a statement, the body clearly showed defensive wounds on his arms. Also by the observance of partial tracks found near the man, authorities are saying that it seems a cub and a female grizzly were both there at the scene. An official forensic autopsy is scheduled for Monday.

Evidence has been gathered at the scene by park rangers and wildlife biologists in attempt to recover bear DNA. Due to recent heavy rains in the area though, the procedure has not proved to be successful in its goal.

“We may not be able to conclusively determine the circumstances of this bear attack, but we will not risk public safety,” Yellowstone National Park Superintendent Dan Wenk said, according to the statement. “We are deeply saddened by this tragedy and our hearts go out to the family and friends of the victim as they work to cope with the loss of someone who loved Yellowstone so very much.”

There are over 600 grizzly bears known to be in the Greater Yellowstone Ecosystem, and although the park warns people to stay atleast 100 yards away from the bears, there have been four reported fatalities since 2010.