The linked Article doesn’t say anything about any pets. The quote you used is from Waymo, who didn’t know anything about the cat besides the fact that their robot car ran it over.
The tag in the picture is a rabies tag, not an ownership tag. The collar is to hold the rabies tag, and the bell is attached to the collar.
The article has quotes from several community members grieving the loss of the cat, yet not from any supposed owner and doesn’t even mention any owner. The cat is very obviously a local stray.
Nowhere in the article does it mention the cat having an owner, besides the statement released by Waymo.