A Yellowstone National Park spokesman says two more grizzly bears have been captured as part of an investigation into last month's mauling death of a Michigan man.
Park spokesman Al Nash said Wednesday that the adult male bears were captured Sunday in the Hayden Valley area, where 59-year-old John Wallace of Chassell, Mich., was killed Aug. 25 while hiking alone in the park's backcountry.
Nash says hair samples were taken from the animals for DNA testing. The bears were fitted with radio collars for tracking and released.
Park officials have said they will kill the bear that mauled Wallace if they can confirm its role through DNA analysis. Another bear captured last week also was released after being radio collared.
Wallace's death was the second fatal mauling in a month, the first in 25 years.
There were no eyewitnesses to the attack on Wallace, 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, park spokesman Al Nash said last week. 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 man's body was discovered five miles up the Mary Mountain trail north of Old Faithful. Authorities said Wallace likely was killed 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.
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 happened about eight miles from where Wallace's body was found.
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.
Overall, 295 bear-human conflicts were recorded by researchers in the park and adjacent areas of Wyoming, Montana and Idaho in 2010. Three out of every four of those involved bears killing livestock or damaging property to get food, garbage, livestock feed or other "human-related" foods.
Almost all occurred outside the boundaries of Yellowstone and neighboring Grand Teton National Parks, which combined recorded only six run-ins between people and bears.
But the potential for problems between bears and humans inside Yellowstone could be seen in the park's 435 "grizzly bear jams" — roadside traffic jams caused by visitors viewing grizzlies. That is the highest number seen since the current government management plan for the animals was adopted almost three decades ago.
The bear jams were fueled by a record 3.6 million people visiting Yellowstone last year.