The sow, estimated to weigh 300 to 400 pounds, was lured into a trap fashioned from culvert pipe covered by the dead victim's tent Wednesday evening. The bear tore down the tent again and was caught in the trap, said Montana Fish, Wildlife and Parks spokesman Ron Aasheim.
By Thursday morning, two of the year-old bears had been caught and the third could be heard nearby, calling out to its mother.
Montana wildlife officials on Thursday identified the man killed in the mauling as Kevin Kammer, 48, of Grand Rapids, Mich. The bear pulled Kammer out his tent and dragged him 25 feet to where his body was found, Aasheim said.
The other victims, Deb Freele of London, Ontario, and an unidentified male, have been hospitalized in Cody, Wyo.
Fish, Wildlife and Parks Warden Capt. Sam Sheppard said he was confident they had captured the killer bear because it came back to the same site where the man was killed early Wednesday.
Sheppard described the rampage - in which campers in three different tents were mauled as they slept - as a highly unusual predatory attack.
"She basically targeted the three people and went after them," Sheppard said. "It wasn't like an archery hunter who gets between a sow and her cubs and she responds to protect them."
Officials have said the sow will be killed after DNA evidence confirms it was the same bear that attacked the victims.
"Everything points to it being the offending bear, but we are not going to do anything until we have DNA samples," Aasheim said.
State and federal wildlife officials will determine the fate of the cubs. Sheppard said they are unlikely to be returned to the wild because they could have been learning predatory behavior from their mother.
Freele said Thursday she was bitten on her arm and leg before she instinctively played dead so the animal would leave her alone.
Appearing on network morning shows from a Wyoming hospital, Freele said she woke up just before the bear bit her arm.
"I screamed, he bit harder, I screamed harder, he continued to bite," she said, adding that she could hear her bones breaking. "I told myself, play dead," she said. "I went totally limp. As soon as I went limp, I could feel his jaws get loose and then he let me go."
Freele said the bear was silent.
"This, to me, was just an absolutely freaky thing," she said. "I have to believe that the bear was not normal. It was very quiet, it never made any noise. I felt like it was hunting me."
Freele suffered severe lacerations and crushed bones from bites on her arms. The male survivor, thought to be a teenager, suffered puncture wounds on his calf.
The bear attack was the most brazen in the Yellowstone area since the 1980s, wildlife officials said.
One camper said he heard the screams from two of the attacks, which started around 2 a.m. Wednesday.
Don Wilhelm, a wildlife biologist from Texas, thought the first scream was just teenagers, maybe a domestic dispute in the middle of the night. He tried to go back to sleep, stifling thoughts that a beast might be lurking outside his family's tent.
Minutes later, another scream - this one coming from the next campsite over, where a bear had torn through a tent and sunk its teeth into Freele's arm.
"First she said, "No!' Then we heard her say, 'It's a bear! I've been attacked by a bear!"' said Wilhelm's wife, Paige.
By that point, the bear already had ripped into another tent a few campsites away, chomping into the leg of a teenager who had been sleeping with his family. The solo camper who was killed was at the other end of the Soda Butte Campground.
Then, the screams stopped.
After a quick parental back-and-forth over whether to shield their 9- and 12-year-old sons with their bodies or make a break for it, the Wilhelms took advantage of the silence and darted to their SUV.
They drove around the campground, honking their horns and yelling to alert other campers. Along the way, they met with a truck leaving the campground with the teenage victim, who apparently tried in vain to fight off the bear by punching it in the nose.
"It was like a nightmare, couldn't possibly happen," Paige Wilhelm said later.
In 2008 at the same campground, a grizzly bear bit and injured a man sleeping in a tent. A young adult female grizzly was captured in a trap four days later and taken to a bear research center in Washington state.
The latest attack had residents and visitors to Cooke City on edge. Many were carrying bear spray, a pepper-based deterrent more commonly seen in Yellowstone's backcountry than on the streets of the national park satellite community.
"The suspicion among a lot of the residents is that the bear they caught (in 2008) was not the right one," said Gary Vincelette, who has a cabin in nearby Silver Gate.
Sheppard, the warden captain, said there was no truth to that.
The grizzly involved in the latest attack showed no outward signs of sickness or starvation that might have explained its unusual behavior, said Fish Wildlife and Parks spokeswoman Andrea Jones.
About 600 grizzly bears and hundreds of less-aggressive black bears live in the Yellowstone area.
The region is pasted with hundreds of signs warning visitors to keep food out of the bruins' reach. Experts say bears who eat human food quickly become habituated to people, increasing the danger of an attack.
Yet in the case of the Wednesday's attack, all the victims had put their food into metal food canisters installed at campsite, Sheppard said.
"They were doing things right," he said. "It was random. I have no idea why this bear picked these three tents out of all the tents there."
The 10-acre Soda Butte Campground in Gallatin National Forest has 27 sites.
Two other campgrounds were also closed while the attacking bear or bears remained at large.
Associated Press Writer Amy Beth Hanson in Helena contributed to this report.