A grizzly bear sow with two cubs was euthanized after being linked to both hiker deaths this summer in Yellowstone National Park.

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Yellowstone Park Spokesman, Al Nash, says the decision to euthanize came after DNA tests of hair and scat from the sow bear responsible for a hikers death in July were matched to samples from the site of a second hiker death in August.

"Because we don't have an eyewitness we're never going to know specifically how this sow was involved in the second incident, but because this bear had been at the scene of two fatal attacks, our park managers and biologists determined that it was in the best interest of park visitors and staff that we capture and euthanize the bear."

Park officials described the first attack on Brian Matayoshi as defensive, but, as Nash explained, there were no witnesses to the death of John Wallace in late August and so the bear's role, if any, will never be known.

Nash says there were at least nine other bears in the area prior to the incident.

"We've captured a few bears, but none of the samples from those bears have been linked to the incident site, but we continue capture operations, were continuing over-flights and we will see if it might be possible for us to link any other bears to this second fatal attack."

The 6 to 7 yr-old, 250 pound, sow grizzly was captured last week and euthanized on Sunday. The cubs will be placed in the Grizzly & Wolf Discovery Center in West Yellowstone, Montana.  Nash says the decision was not easy.

"No decisions like this are easy decisions. This has been a very difficult and challenging year for our staff."