You have to blame both of them... She might be 16 but she knows what she was getting into. However, the majority of the blame should go to the adult.
I don't know about the law in CA but if it's like some other states, he could get off by getting her parents to say that he and the girl is engaged and they and she consent to the relationship.
"If" she's Hmong that could be the case of her parent and her giving him a break. I do blame that 16 yo because she can get out of the house to be with him secretly or letting this go on for a month. Mr. Yang we don't know what is on his mind for being with that 16 yo.
CA laws can always change depending on how the judge see it. 14-16 yo and if you do consent it will change the case to be no longer rape, sexual, etc. They are just caught so there is consequences for Mr Yang to face. If not caught they are just like many of my husband young client/adults talking about when they are 13-16 yo and selling their body in exchange for $$, etc. They know it is wrong but they need $$. Just like this 16 yo know it is wrong but she like Mr Yang enough to continued it...