"Happiest dog in the world. Very playful. She was a close part of the family. They said the mountain lion was three times as big as my dog... and that's scary," Jonathan Slater, dog's owner, said.
Authorities said when Princess' owner came outside on Wednesday morning, the mountain lion didn't flinch.
"This mountain lion stood its ground and became aggressive towards the resident by growling at him and getting ready to jump on the resident," Chief Rod Jones, Fontana Police Department, said.
Even after police officers arrived, the mountain lion didn't back down.
"A couple of our officers got within 10 to 20 feet of the mountain lion. The officers retreated and fired several rounds," Jones said.
It's unknown if the cat was hit. Even after an exhaustive search using infrared cameras, the mountain lion hasn't been located. Officials warn families to keep their pets indoors.
"It's really scary, even going to our cars at night," Camille Denzler said. "We really don't have anything to protect ourselves."