Wildlife officers believe the poorly conditioned older male grizzly had wandered to the edge of town after lingering around the Ingraham Trail the past couple of weeks.
As far as the Department of Resources, Wildlife, and Economic Development can tell, the bear is the first-ever recorded grizzly to enter Yellowknife. Their normal range begins about 200 kilometres north into the Barrens.
"It was a bear that had seen a lot of wear on his teeth; it was in poor physical condition, looking for food," said senior wildlife officer, Raymond Bourget.
"With the amount of fat he had, he would not have survived denning up."
Bourget believes the bear was following the caribou, who had come earlier and closer to town than usual this year.
On Tuesday night, the department received a report that a large "brown" bear had been spotted near the Dettah junction on the Ingraham Trail, but officers couldn't locate it when they came to investigate the following day.
Later that evening a Dettah resident spotted the bear at the community dump. The next morning it was seen crossing Yellowknife Bay, heading towards Con Mine.
By the time officers arrived just before 9 a.m., the bear had moved inland and, judging by its tracks, was following a snowmobile trail towards Kam Lake.
Bourget said officers got their first look at the bear after it moved back onto the bay about one km past Negus Point. It was then, at a range of about 10 metres, the grizzly charged.
Officers shot it with 30.06 rifles.
"From the time they saw the bear to the time that it charged at them, it was probably about five and 10 seconds," said Bourget.
Bourget estimated the bear weighed about 400 lbs, and had only about one centimetre of fat on its back. A male grizzly would normally have about 10 centimetres of fat this time of year.
An autopsy was performed yesterday, where cysts -- indicating pneumonia -- where observed on its lungs. They also found that it had got into a bad scrape with a porcupine.
"It had porcupine quills in one of its legs and on the side of his face," said Bourget. "They were infected."
The department had received two reports of a brown-coloured bear with a hump on its back being sighted near Powder Point on the Ingraham Trail, starting two weeks ago.
Bruce Donlan, who lives in a cabin a few kilometres east of Powder Point, said he saw some unusual bear tracks in the snow about three weeks ago.
"The tracks looked much bigger than they would be with a normal black bear," said Donlan.
Wildlife officers initially were uncertain if they were made by a grizzly or just a very large black bear.
Donlan said the stories have been rampant and confusing ever since he found the tracks.
A couple weeks ago, a friend told him he was warned by several people as he was out for a walk by Powder Point that a grizzly had been spotted nearby, and that he should be careful.
"The stories go from one to another," said Donlan.
Jamie Bastedo, a local naturalist and author of the book Tracking Triple Seven -- about a family of grizzlies denning in the Barrens -- said he has been following a number of unusual animal sightings recently with great interest.
"Buffalo into town, there's coyotes onto Frame Lake: it kind of has an (Alfred) Hitchcock flavour to it," said Bastedo.
"We can respond with fear and become more of a fortress mentality, or we can respond with fascination and acceptance."