SIMI VALLEY (CBSLA) — Pet owners were warned to be on alert Thursday after a mountain lion killed one dog and attacked another in Simi Valley.

A miniature schnauzer was killed early Thursday by the mountain lion, which had been reported Wednesday night by another family whose dog was also attacked.

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A man who identified himself only as Brian D. said his sister had gotten up early because her 10-year-old dog Pumbaa was barking and let him out – not knowing about the mountain lion attack the night before.

“She opened the door, and I think she went out first, and she saw the mountain lion,” he said. “Her dog charged underneath her legs towards the mountain lion and the mountain lion snapped it right off.”

He said his sister jumped on the mountain lion to try and pry its jaws open to save her dog, but was unsuccessful. The dog had been thought of as family, and his daughter is distraught over the loss.

The mountain lion had first been reported to authorities at about 10 p.m. Wednesday by a family whose dog was attacked as they took him on a walk. Robert Kharitonoe said he had seen police surround the mountain lion.

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“It got spooked and started to walk across the street, actually towards my car,” he said. “That was very, very scary. Yeah, I rolled up my windows immediately, I tried to stay as calm as I could.”

The dog, a havanese named Sammy, suffered several puncture wounds but is expected to be OK.

Video shows the mountain lion had been prowling the area as early as Tuesday.

Residents like Dmitri Orloff are taking no chances. He drove his German shepherd to another neighborhood for her walk.

“It’s a big dog, but it’s a domesticated dog. It’s not gonna defend itself against a wild animal,” Orloff said. “A wild animal sees its prey, and it’s gonna get the upper hand every time.”

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Fish & Wildlife officers are still in the area, searching for the mountain lion, which has been collared, but the device does not seem to be working.