SANTA ROSA, Calif. (KRON) – Some residents of Sonoma County, California, are concerned about mountain lions after a disturbing video captured one entering a house, attacking a dog, and dragging the dog by its neck into the backyard.

The incident took place last week when a Bennett Valley resident left her sliding glass door open. The homeowners heard a commotion soon after and realized the cougar had targeted their border collie inside the house.

Video of the incident shows a snarling mountain lion standing over a motionless dog.

Local resident Ron Crane, who witnessed some of the attack, said another neighbor “came over and fired a shot in the air” to scare off the animal.

The dog was eventually rescued and survived.

“[The dog’s owner] thought it was a goner for sure,” Crane said.

A mountain lion stands over a motionless dog after dragging it from a California home. (Image courtesy Ron Crane)

The cougar, meanwhile, remained outside the house and continued staring through the glass door for several hours.

It went off and killed two goats before wildlife biologists located and euthanized it over the weekend.

“That could have easily have been a kid,” Crane said. “The local activist organization knew this cat had erratic behavior problems for a while.”

Mountain lions’ primary source of food in California are deer.

“The deer are dwindling, and these kinds of things are going to happen more often,” said Crane, who’s also a local rancher. “I’m 49, and when I was in high school, there were no sightings. The population was not as big as it is now.”

Mountain lions are naturally afraid of humans, according to the California Department of Fish and Wildlife. But this lion was “unusually old” and displayed behavior that’s not common, according to Audubon Canyon Ranch, a North Bay environmental conservation group.

Audubon Canyon Ranch identified the euthanized lion as P1, a female cougar who was about 16 years old.

ACR researchers said they are “saddened” by P1’s death, however, “we believe that the lethal removal of P1 was the right course of action.” P1 was collared and tracked by ACR’s Living with Lions project for eight years.

Living with Lions principal investigator Dr. Quinton Martins acknowledged that “clearly, something was wrong” with that particular animal.

“She was very old for a mountain lion which may have led to issues related to aging including tooth wear, slowed responses, weakened senses, and possibly other health issues,” Martins wrote. “In recent weeks, she was more willing to put herself near human activity with people having frequent sightings of her, as well as feeding almost exclusively on livestock, all of which is very unusual behavior.”

Audubon Canyon Ranch added that it is rare for a mountain lion to reach P1’s age. She had also reared three litters of kittens since 2016, the agency said.