CODY, Wyo (Reuters) - A hiker found dead on a backcountry trail in Yellowstone National Park last week was killed by a grizzly bear in the park's second fatal bear mauling this summer, park officials said on Monday.
The two fatal attacks occurred within several miles of one another, and park officials were examining whether the same bear was involved in both incidents, a Yellowstone spokesman said.
The body of John Wallace, 59, who was hiking alone and visiting from Chassell, Michigan, was discovered on Friday morning by two other hikers along the Mary Mountain Trail amid signs of grizzly activity at the scene, including bear tracks.
But it had not been clear until an autopsy was performed whether Wallace was the victim of a bear attack or if his body had been scavenged after he had died by other means.
"Results from an autopsy conducted Sunday afternoon concluded that Wallace died as a result of traumatic injuries from a bear attack," a U.S. Park Service statement said.
The exact circumstances of the attack remained a mystery as there were no witnesses, but park Superintendent Dan Wenk told Reuters that once the grizzly involved was positively identified "that bear will be removed from the population."
"The bear caused significant injuries to the hiker," Wenk said. "That's enough to know without a description of exact circumstances."
Wallace had pitched a tent in a park campground sometime on Wednesday and was believed to have been killed later that day or on Thursday, park officials said.
His death comes a month after a female grizzly attacked and killed another man who inadvertently surprised the bear and her two cubs as he and his wife were on a hike, marking the first fatal bear mauling in Yellowstone since 1986.
Bear managers opted not to capture or kill that grizzly because they concluded it had been acting in a purely defensive -- as opposed to predatory -- manner to protect its young and had no previous history of conflicts with humans.
But park spokesman Al Nash said it was possible the same bear also was behind the latest attack, and that DNA from hair samples collected at both scenes would be compared to make that determination.
"We will be able to definitively answer that question once DNA tests on the hair samples have been completed," Nash said.
The July mauling occurred near the start of the Wapiti Lake Trail, several miles from the scene of last week's attack, a distance within the roaming range for grizzlies, he said. The female grizzly from July's incident is not the only suspect.
Wenk said any bear that returns to the site of the latest mauling, about 5 miles west of the Hayden Valley trailhead, would be trapped so its DNA could be matched against samples of fur and feces found at the scene now being tested.
The park euthanized a 4-year-old male grizzly earlier this month after that 258-pound animal charged a man sitting on a hiking trail near Yellowstone Lake.
That hiker was unhurt but the bear involved was determined to pose a hazard to park visitors because of previous encounters.
Despite the recent flurry of Yellowstone grizzly confrontations with humans, Wenk said, "I don't think we're looking at a trend." He added that bear injuries in the park were still exceedingly rare.
Yellowstone averages just one bear-related human injury for every 3 million visitors, or about one a year, though no visitors were hurt by bears in all of 2010.
The Mary Mountain Trail runs 21 miles one way across Yellowstone's central plateau to the Nez Perce trailhead between Madison and Old Faithful. Signs posted warn of grizzly activity, and hikers are advised to travel in groups of six, make noise and carry bear repellent spray.
Additional reporting by Laura Zuckerman; Writing by Steve Gorman; Editing by Jerry Norton and Cynthia Johnston