Officers with the B.C. Conservation service say a mother cougar was caught and put down hours after her three cubs were also destroyed near Penticton, B.C.
Conservation officer Sgt. Jim Beck said the family of four had been spotted several times over the past few weeks and that the four cats showed little fear of humans.
Officers were concerned that the habituated mother had been teaching the cubs to hunt in urban areas.
He said, the animals were spotted a "multitude" of times on Friday, including once within a kilometre of an elementary school.
The group wasn't fazed when officials tried to scare them away.
"[The mother] was displaying odd behaviour," Beck told CBC News. "She was basically teaching her children to ignore people ... all very concerning from a public safety standpoint."
The animals were seen several more times within the city over the weekend. On Saturday, it was discovered that they'd killed a deer in someone's backyard.
On Sunday, the mother cougar stalked a woman and her pet dog while they were out for a walk.
By the next morning, the conservation office had determined that the animals were a threat to the public.
Conservation officers found the family hiding up a tree in a residential area on Tuesday around 10 a.m. The three young cats were put down, but the mother escaped.
Parents and pet owners were advised to keep a close watch on small children and animals while officers continue their search.
Beck said tranquillization and relocation wasn't an option for the cats because much of the region's deer population is confined to urban areas during the winter.
The abundance of prey would've drawn the cougars back into developed areas, the officer said.
He estimated that the destroyed mountain lions were about a year old.
'Human safety has to take precedence'
Beck said he's never seen a mountain lion be so at ease among humans in his more than 30 years with the conservation service.
"She's by far the most comfortable cougar around development and people I've ever seen in my career," he said.
The officer said the animals are typically shy and wary of people but can be "unpredictable."
"Under that furry exterior that's very beautiful are a set of canines that are purely designed for killing. They're a predator at the top of the food chain," Beck said.
The officer stressed that B.C.'s cougar population isn't in danger.
"Human safety has to take precedent," he said.
With files from CBC's Kamil Karamali