Living in the area of the Central Valley for 30 yrs, (Planada is only about 50 miles away), it is my opinion that this could absolutely be a stranger/slight acquaintance murder and abduction of the baby.
I was shocked when about 10 years ago a pregnant woman was kidnapped about 5 blocks from our house, and was found murdered with her baby cut out of her abdomen. The "3 strikes You're Out" law came from a murder 3 blocks away. Steven Stayner (kidnap victim) was a local, as was Marcus Wesson - 6 blocks away, (incest & had all 7 or 8 of his children murdered by his eldest daughter.)
For some reason people think they can get away with crimes here. Maybe because there is TONS of farmland, with small cities spread out here and there. But news travels fast. And we have REALLY tough cops here.
My point - they WILL catch the perps.