Rangers at Denali National Park continue to investigate last week's fatal bear mauling, the first on record inside the popular 6-million-acre wilderness area, the National Park Service says.

Park Service officials also said Tuesday that violent bear activity -- including two recent reports of grizzlies attacking other bears within miles of the fatal mauling -- did not warrant closing the area where the man died.

Richard White, a San Diego, Calif., pharmacologist three days into his five-day solo backpacking trip, spotted a large adult grizzly while walking on a gravel bar, according to the National Park Service. White, 49, took more than two dozen photos of the bear, which appeared to notice and approach him in the last pictures before it attacked from as close as about 50 yards away, park spokespeople said.

White, who did not have bear spray or a firearm, should have backed away from the bear to give it a 300 yard buffer required by his backcountry permit, according to the Park Service. News reports say White left behind a wife and young daughter.

According to the Park Service, rangers think the bear pounced on White, then dragged him to some bushes where it stashed his body, fed on it, and then menaced rangers trying to recover the remains hours after other hikers reported finding White's backpack Friday, as well as blood and torn clothing.

The rangers shot at the grizzly and missed as it circled them in the thick brush and descending darkness, the Park Service said. An Alaska Wildlife Trooper firing a rifle from a helicopter killed it Saturday, the Park Service said.

According to park policy, if the bear had left the body after the attack, it would not have been shot, said park spokeswoman Kris Fister. But because it stayed and menaced the rangers, it was killed, she said.

About 130 square miles of wilderness that were closed to hiking after White's death remained so Tuesday. White's body was flown to the state medical examiner's office in Anchorage, Fister said.

Rangers were at the site of the attack Tuesday looking for footprints, drag marks and any other evidence, Fister said.

"We're trying to line up where the photos were taken from," Fister said. "It's rained for a couple days by now, so we're pretty certain a lot of (the footprints) have been obliterated. So most of what we're doing is analyzing the photos."

Fister confirmed that the Park Service received at least two reports by other hikers of violent, but normal, bear activity in the same area or nearby, both within a week of the mauling that killed White.

One group said they'd seen an adult grizzly kill and feed on another adult bear Aug. 11 along the Upper Toklat, not far from where White died. A ranger hiked in to take a look and didn't find any sign of a dead bear, Fister said.

"There would have been something. I mean, they don't eat everything. There would've been skin, bones," she said.

The report was deemed unsubstantiated and rangers left the area open.

A few miles away on Aug. 21, some hikers saw a male grizzly attack a sow bear and her cub, killing the cub, Fister said. The sow wounded the larger male, leaving a gash on its back, which was not present on the bear that killed White, the park spokeswoman said.

"It had been determined that it was not the same bear," she said.

That area was closed for a day or so, and neither report led park officials to think anything was strange about the bears' behavior, Fister said. There was no evidence of a dead, cached bear at the one site, and, though it's unfortunate for bear cubs, their most dangerous predators are other bears, she said.

"That's what they do," Fister said. "It wasn't any different than usual."

Park officials say the ongoing investigation will show exactly what happened, and they aren't blaming either the bear or White, its victim. But for now if appears as though White made a fatal mistake in staying close to the bruin, Fister said.

"This happens on a regular basis. It's happened to me when I go over a ridge, and there's a bear. A more prudent person would've begun to move away," Fister said.

A little fewer than 2,800 people have gotten permits to backpack in Denali this year, Fister said. There were about 3,300 in 2011 and 3,500 in 2010, she said.

With that many backcountry visitors, dangerous encounters with bears in the park happen on a regular basis and will likely continue to happen, Fister said.

"This bear acted more aggressively and far more predatorily than any other incident here," Fister said. "It's an anomaly ... We hope we don't have another incident like this. It had been almost a hundred years."

"Maybe we've been fortunate, and maybe it speaks to how many people are aware. Maybe some of them have just been lucky."

Reach Casey Grove at casey.grove@adn.com or 257-4589.