BILLINGS, Mont. - Yellowstone National Park officials captured a grizzly bear Friday near the site of a fatal attack, but they were not sure whether it is the bruin responsible for a Michigan hiker's death last week, a park spokesman said.

The 25-year-old, 420-pound male grizzly was to be collared and released back into the park after officials take hair samples, spokesman Al Nash said.

If the bear's DNA matches that of samples found at the site and additional evidence from the scene links the grizzly to 59-year-old John Wallace's death, the bear will be tracked down and killed, Nash said.

"If we feel that we can positively link a bear to the incident site, then the determination has been made that we will kill the bear. The DNA is an important part of that, but it's not the only part of that," he said.

Park officials had sent hair samples collected near Wallace's body to be tested, but those DNA results proved to be inconclusive, Nash said. More samples are being sent to conduct another round of tests.

There were no eyewitnesses to the attack, and a DNA match alone won't be conclusive in determining whether a bear was responsible for the attack or happened upon the body afterward, Nash said. That means additional evidence would be needed to make that conclusion, which may be difficult.

"The Hayden Valley is an area that is typically known for a significant amount of bear activity, so we may never capture and positively identify the bear or a bear that was involved in this incident," Nash said of the section of the park. "We're working with the hope that we can ultimately resolve this attack, but we may not be able to do so."

The body of the man from Chassell, Mich., was discovered a week ago five miles up the Mary Mountain trail north of Old Faithful. Authorities said he likely was killed last Wednesday or Thursday during a solo hike along the trail, which is closed in the spring because it passes through an area frequented by grizzlies feeding on the carcasses of bison that died over the winter.

An autopsy determined Wallace died from injuries sustained in a bear attack.

It was the second fatal bear attack in the park this summer. In July, a female bear with cubs attacked a couple from California, killing the man before fleeing. Park officials then concluded the sow was acting to protect her cubs and let it go.

That attack, the first inside the park in 25 years, happened about eight miles away from where Wallace's body was found.

The Mary Mountain trail and others nearby in the Hayden Valley section remained closed as Yellowstone officials prepared for a busy Labor Day weekend filled with holiday visitors. Wildlife officials have relocated bear traps to new areas, but they report flights over the Hayden Valley area have resulted in very few bear sightings.

Wallace's mauling death came as run-ins between humans and the Yellowstone region's growing bear population reached record levels last year, according to a report this week by the Interagency Grizzly Bear Study Team, a group that includes state, federal and tribal wildlife agencies.

Nine human injuries were tallied in 2010 - almost double the long-term average of five a year. Among them were two fatal maulings east of Cody, Wyo., and near Cooke City, Mont., the first for the region in decades.