The attack in Churchill, on the shores of Hudson Bay, came after the 69-year-old man stepped outside his home to investigate a "commotion" on the street about 5 a.m., said RCMP spokeswoman Tara Seel.
A 30-year-old woman, one of three pedestrians who had been confronted by the bear, was also injured, Seel said.
"It was right in the town," she said.
"Pedestrians were walking in the town and were surprised by a polar bear. A homeowner heard the commotion and exited his home, at which time he was attacked by the polar bear.
"Another local resident was driving a vehicle and charged it toward the bear and scared the bear off."
The man and woman were both taken to hospital. Police said the man suffered multiple lacerations.
Resident Joe Myles said on his Facebook site that he saw three bears. Myles wrote that he was outside having a cigarette break during his night shift at a hotel when a co-worker yelled about a bear sighting.
"I ran out to see a huge mama bear and her cub scurrying across the street from the back alley. Then we started hearing shots, then screaming and yelling, then more shots."
Myles said another bear came up the alley and "stopped and stared."
"We creeped back towards the door and had it half open just in case it came at us. Inside, the morning cook was frying bacon, which obviously interested the bear."
When the bruin made a move towards them, they ran inside and shut the door.
The sightings were reported to Manitoba Conservation, who were able to respond quickly, said spokesman Glen Cassie.
Officers had been patrolling Churchill earlier that night as part of their regular precautions on Halloween night.
Several conservation officers circle the town in a helicopter to see if there are any bears around eyeing trick-or-treaters. Emergency vehicles are set up around the perimeter with their lights flashing to deter any curious creatures from checking out candy bags.
Several bears had been pushed back from town and the officers had just ended their patrol, Cassie said.
"They were back on the scene within minutes."
He said one bears was shot and wounded. As officers tracked it, they came across a second bear and shot it dead.
The injured bear was found shortly after, dead.
Cassie said it's not normal practice to automatically shoot bears within the town, but this situation required it.
"When an attack has occurred and now there's other people out on the street trying to get people and rescue somebody that's injured, (officers) sometimes have to take additional measures."
The cub was tranquilized and taken to a holding facility. Cassie couldn't say what will be done with it.
"Decisions will be made at a later time."
It is not the first polar bear attack in Churchill this fall.
In September, a bear chased resident Garett Kolsun, trapped him on the porch of a bakery and swiped at him with a paw.
Kolsun pulled out his cellphone and the light startled the bear, which backed into a flower pot. That distracted the animal enough to give Kolsun a chance to run away.
Kolsun had only superficial puncture wounds and scratches.
Churchill is near important polar bear summer habitat. The animals come through the area every year about this time when they move from the tundra back to seal-hunting territory — the pack ice that forms every winter over Hudson Bay.
In recent years, their return to their winter hunting ground has been delayed by the increasingly late formation of the sea ice caused by climate change.
— By Bob Weber in Edmonton
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