A resident of the Oakridge Mobile Home Park captured graphic photos of the incident.
Rey Constante says the dog, a pit bull named Gigi, was being walked by her owners when they encountered a mountain lion. They apparently tried to fight back.
"It was a cute, beautiful, friendly pit bull - harmless. So, I was saddened to see the dog just dying in front of me and nothing I could do to save the dog," Constante said.
The mountain lion ended up getting spooked by a car and took off into the nearby hills.
Neighbors in the area are worried it will return and say they are taking precautions.