My ex girlfriend and I had a child about 18 months ago. The mother is Cambodian. I am American. He has my last name and I am on the birth certificate. He is also an American citizen. He cannot get Cambodian citizenship either. We have split up and despite considerable financial support from me she continues to try and hurt me whenever possible even at the expense of my child. I have ask for custody but she refuses. She was abussive in our relationship and I would like custody of my son. Does anyone know what my legal options are or who I contact about it? There does not seem to be a lot of info on this. 

Pm sent.

To be clear, are them mother and child now living in Thailand? If so under what sort of visa? Or are they in Cambodia?

Yes. Mother and child live in Bangkok. No visa or tourist visa. I have businesses outside of the country.