A self-taught bear expert who once called Alaska's brown bears harmless was one of two people fatally mauled in a bear attack in the Katmai National Park and Preserve (search).

The bodies of Timothy Treadwell (search), 46, and Amie Huguenard, 37, both of Malibu, Calif., were found Monday at their campsite when a pilot arrived who was supposed to take them to Kodiak, state troopers said Tuesday.

Treadwell, co-author of "Among Grizzlies: Living With Wild Bears in Alaska," spent more than a dozen summers living alone with and videotaping Katmai bears. Information on Huguenard was not immediately available.

The Andrew Airways pilot contacted troopers in Kodiak and the National Park Service (search) after he saw a brown bear, possibly on top of a body, at the camp near Kaflia Bay.

Park rangers encountered a large, aggressive male brown bear within minutes of arriving. Ranger Joel Ellis said two officers stood by with shotguns as he fired 11 times with a semi-automatic handgun before the animal fell, 12 feet away.

"That was cutting it thin," said Ellis, the lead investigator. "I didn't take the time to count how many times it was hit."

The victims' remains and camping equipment were flown Monday to Kodiak. Ellis said investigators hope to glean some information from video and still cameras.

As the plane was being loaded, another aggressive bear approached and was killed by rangers and troopers. The bear was younger, possibly a 3-year-old, according to Bruce Bartley of the Alaska Department of Fish and Game.

The victims' bodies were flown to the state medical examiner's office for autopsy.

Dean Andrew, owner of Andrew Airways, said the pilot was too upset to comment. The company had been flying Treadwell to Katmai for 13 years and Huguenard for the last couple of years. Andrew said Treadwell was an experienced outdoorsman.

Treadwell was known for his confidence around bears. He often touched them, and gave them names. Once he was filmed crawling along the ground singing as he approached a sow and two cubs.

Over the years, Park Service officials, biologists and others expressed concern about his safety and the message he was sending.

"At best he's misguided," Deb Liggett, superintendent at Katmai, told the Anchorage Daily News in 2001. "At worst he's dangerous. If Timothy models unsafe behavior, that ultimately puts bears and other visitors at risk."

That same year Treadwell was a guest on the "Late Show with David Letterman," describing Alaska brown bears as mostly harmless "party animals."

In his book, Treadwell said he decided to devote himself to saving grizzlies after a drug overdose, followed by several close calls with brown bears in early trips to Alaska. He said those experiences inspired him to give up drugs, study bears and establish a nonprofit bear-appreciation group, called Grizzly People.

Grizzly and brown bears are the same species, but "brown" is used to describe bears in coastal areas and "grizzly" for bears in the interior.

The deaths were the first known bear killings in the 4.7-million-acre park on the Alaska Peninsula.