(CNN) -- A grizzly bear was euthanized Friday after a DNA test determined that it mauled three campers -- one of them fatally -- in a remote area of Montana, an attack that has perplexed wildlife experts.
"We just can't figure it out," said Ron Aasheim, a spokesman for Montana Fish, Wildlife & Parks. "It doesn't make any sense."
All the food in the campground was stored properly in bear-proof containers; the attack was unprovoked; the bear had no history of attacking humans, Aasheim said. "It's a head scratcher."
The incident unfolded around 2 a.m. Wednesday, when a caller to the Park County Sheriff's Department said someone had been bitten in Soda Butte Campgrounds outside Yellowstone National Park.
"My daughter's boyfriend got bit by a bear just a little bit ago; there's another lady down there that's screaming," the caller to 911 told police.
When parks officials showed up, they "found a dead man, partially consumed, 25 feet from his tent," Aasheim said.
The body was identified as Kevin Kammer, from Grand Rapids, Michigan, who had been on a solo fishing trip, Aasheim said. Reached at the family's house, Kammer's son said he did not want to discuss the matter.
The carnage continued, though with less dire results: 21-year-old Ronald Singer of Alamosa, Colorado, was with his girlfriend and her father about 100 yards from Kammer when he was bitten on the leg.
"I felt the tent just slide two to three feet and this giant thing was on my leg," Singer told NBC's "Today Show."
"I turned the light on and I screamed while he was punching the bear and the bear took off," said Singer's girlfriend, Maria Fleming.
Another 400 yards away Deb Freele, 58, of London, Ontario, was with her husband when she was attacked. "I screamed and he bit down harder," she told ABC's "Good Morning America." "I screamed some more and he continued to bite and shake and I could hear my bones breaking. I decided I was just going to play dead, and I went completely limp like a rag doll and, after a few seconds, he loosened his grip and he left."
The three attacks likely occurred within about an hour, Aasheim said.
Park authorities called in a human wildlife attack-response team, which searched the campground -- from which the "couple of dozen" other campers had been evacuated -- for evidence, including hair and scat samples, Aasheim said.
Among the finds: a bear tooth fragment.
Once the evidence had been collected, officials set up Kammer's tent, attached it to a baited bear trap -- and waited.
At 6 p.m., the female returned, tore the tent down and was trapped; on Thursday, her three yearling cubs were also trapped, he said.
DNA tests matched bear saliva found on Kammer with the DNA of the mother bear; the broken tooth matched a tooth that was broken in her mouth; and tent and sleeping bag material were found in her scat, he said.
Once the DNA match was made, the animal was euthanized.
Authorities had little choice, said Grey Stafford, director of conservation and communications at the Wildlife World Zoo Aquarium in Litchfield Park, Arizona.
"When you have a dangerous predator like that -- that has no fear of humans -- you've really got a dangerous situation and I think wildlife managers understand there's very little wiggle room here on what to do," he told HLN's "Prime News."
An autopsy will be carried out "to see if there was something haywire," Aasheim said, adding that the autopsy was expected to find human remains in the animal's stomach.
The cubs will be taken to a zoo, he said.
"Obviously, they're not good candidates for being released back in the wild because of that learning event," Stafford said, referring to the possibility that the cubs may have watched their mother attack the campers. "But I do think that, because they're youngsters and they're still rather plastic in their learning, that there is some room for optimism."
Though incidents of bears attacking humans are rare, they are usually associated with food. In 1987, a bear pulled a camper from a tent near West Yellowstone and partially ate him, Aasheim said. But in that case, the man had not been as diligent about storing his food, he said.
And in 2001, an elk hunter was dressing an elk when he was attacked and killed by a grizzly, he said.
"We say a fed bear is a dead bear," he said. "Once a bear starts becoming acclimated to food, once they understand and associate humans or homes with food, that's typically bad. In most cases, those bears end up dead. We relocate them once or twice, unless they've had contact with a human. If they have contact or taste the flesh of a human, they're dead. That is the line they cannot cross."
But Stafford said there is no way to remove all danger. "We have got to remember, as we move further and further into the forests and spend more time in the wild, these kinds of encounters are going to happen," he said.