A grizzly bear that fatally mauled a hiker in Yellowstone National Park was killed after DNA evidence linked the animal to the scene of a second hiker's death a month later, a park official said Monday. 
 
 The decision to euthanize the 250-pound (113-kilogram) female bear was meant to protect park visitors and staff, Superintendent Dan Wenk said. 
 
 However, the investigation remains open, and officials might never know definitively whether the same bear that killed California hiker Brian Matayoshi on July 7 also took the life of John Wallace of Michigan in August. 
 
 Evidence showed multiple bears, including the sow, were near Wallace's body but not if the sow made any contact with Wallace. The bear was allowed to remain free after Matayoshi's death because park officials said it was reacting naturally to defend its two cubs. 
 
 "We made a decision at that time, based on all the information available, that we did not have a bear with a history or a bear that was demonstrating any predatory nature," park spokesman Al Nash said. 
 
 The deaths of Matayoshi and Wallace were the first blamed on a bear inside the park in a quarter-century. Two fatal maulings occurred just outside the park in 2010. 
 
 There were no witnesses to Wallace's killing. He was hiking alone in Yellowstone's Hayden Valley, about eight miles (13 kilometers) from where Matayoshi was killed. The mauling occurred in a backcountry area frequented by bears, and signs posted at trailheads warned visitors to take precautions. 
 
 By the time Wallace was found by other hikers a day after the mauling, one or more bears had fed upon his body, Nash said. Authorities couldn't determine from the evidence whether the sow bear "attacked Mr. Wallace or came upon the scene subsequent to the attack, but we certainly know the bear was at the scene," he said. 
 
 The sow bear was linked to the scene through DNA analysis of hair and scat samples found near Wallace's body, Nash said. 
 
 The two cubs were captured and relocated to the Grizzly and Wolf Discovery Center in West Yellowstone. 
 
 In the aftermath of Wallace's death, park officials said they did not believe the responsible grizzly was the same one that had killed Matayoshi because they found no cub tracks at the scene. Investigators now believe those tracks might have washed away in a rain storm that went through the area before Wallace's body was discovered. 
 
 Chris Servheen, a grizzly bear recovery coordinator with the U.S. Fish and Wildlife Service, said investigators have concluded the sow bear was at the scene for some time. He said details would be released when investigators complete their report into the attack, which is expected to take another month. 
 
 Servheen also said park officials had made the best decision they could after Matayoshi's death, given the circumstances. 
 
 Since the mauling, park officials have captured at least seven bears in the Hayden Valley. DNA, tracks and other evidence from the scene showed at least nine bears were present around the general time of Wallace's death, drawn by two nearby bison carcasses. 
 
 All of the captured bears were radio collared and released. 
 
 An estimated 600 grizzlies live in the greater Yellowstone area, which includes parts of Wyoming, Montana and Wyoming. A recent report showed run-ins between humans and that growing bear population reached record levels last year, with 295 conflicts recorded by researchers. 
 
 Three of every four of those involved bears killing livestock or damaging property to get food, garbage, livestock feed or other human-related foods. Nine human injuries were reported in 2010 _ almost double the long-term average of five a year. ||||| FILE - In this Sept. 6, 2013, file photo, a woman kayaks on Kintla Lake in Glacier National Park, Mont. A grizzly bear attacked and killed a 38-year-old mountain biker Wednesday, June 29, 2016, as he... (Associated Press) 
 
 FILE - In this Sept. 6, 2013, file photo, a woman kayaks on Kintla Lake in Glacier National Park, Mont. A grizzly bear attacked and killed a 38-year-old mountain biker Wednesday, June 29, 2016, as he... (Associated Press) 
 
 HELENA, Mont. (AP) — A grizzly bear attacked and killed a 38-year-old mountain biker as he was riding along a trail just outside Glacier National Park, Montana authorities said. 
 
 Brad Treat and another rider were in the Halfmoon Lakes area of the Flathead National Forest Wednesday when they apparently surprised the bear, Flathead County Sheriff Chuck Curry said. 
 
 The bear knocked Treat off his bike, and the second rider left to look for help, Curry said. 
 
 Authorities found Treat's body at the scene, but not the bear. Wildlife and law-enforcement officials were searching for the grizzly Wednesday evening. 
 
 Treat was a law-enforcement officer with the U.S. Forest Service. 
 
 "Brad was an integral member of our area law enforcement team and a friend to us all," Curry said. 
 
 Treat grew up in nearby Kalispell, where was a standout distance runner in high school, his former coach, Paul Jorgenson, told the Flathead Beacon newspaper. 
 
 "He was a really good runner but he was also a kind-hearted person who cared about people," Jorgenson told the Beacon. 
 
 The second rider, who was not identified, was not injured. Authorities have closed the area, which is about 3 miles away from Glacier's west entrance, for public safety. 
 
 Grizzlies in the Lower 48 states have been designated a threatened species since the 1970s, but their numbers are increasing and so are conflicts between humans and bears. 
 
 The grizzlies in the Glacier area among about 1,000 bears in the Northern Continental Divide Ecosystem, which also includes the Bob Marshall Wilderness south of the park. At least 700 more grizzlies live in and around Yellowstone National Park, which is roughly 360 miles south of Glacier. 
 
 Six people have been fatally mauled by bears in the Northern Rockies since 2010, but those deaths were mainly in the Yellowstone area. Glacier officials say there are usually one or two non-lethal encounters between bears and humans each year inside the park. 
 
 Before Wednesday, there had been 10 bear-related human deaths in Glacier since the park was created in 1910. The last was in 1998, when three bears killed and partially ate a park vendor employee while he was hiking. 
 
 In the most well-known Glacier attacks, bears killed two people in different parts of the park in a single night in 1967. Those attacks became the subject of a 1969 book by Jack Olsen titled "Night of the Grizzlies," and later a documentary by the same name.
– A mama grizzly linked to the mauling death of two hikers in Yellowstone Park has been killed by rangers. Two men were mauled to death in separate incidents over the summer in the first bear killings in Yellowstone in a quarter of a century. Bear DNA found at the site of the first mauling was also found at the site of the second death a month later. In the first attack, a grizzly sow with two cubs chased and killed a man as he hiked with his wife. A report by Yellowstone rangers concluded that a possible "contributing factor" to the mauling was that the couple "ran from the bear while screaming and yelling," and they decided not to track down the grizzly. "We made a decision at that time, based on all the information available, that we did not have a bear with a history or a bear that was demonstrating any predatory nature," a park spokesman told the AP. But the same sow's DNA was found at the site of the second killing of a hiker walking alone—although tracks and DNA from several other bears were also found at the body, and rangers can't be certain which animal killed the hiker. The euthanized grizzly's two cubs were captured and relocated to the Grizzly and Wolf Discovery Center wildlife park in West Yellowstone. An estimated 600 grizzlies live in the greater Yellowstone area.