I think you will find they were coyotes. My brother lives in Socal and he and I have seen them. Friends live up in the canyons in NE LA and their problem is mountain lions and coyotes.
This is the local breed of of wolfdog here. Make great pets. Very playful with humans and other dogs. The neighbors have one.
Californian wolf.
Coyote.
What ever, you need to get a collar for the dog that makes it very hard for a predator to get his teeth around his neck and be careful letting him out.