How to obtain proof of citizenship from an abusive spouse
I am married (living together for 9 years but married for 4 years) to an American citizen (naturalized 8 months ago). He has been physically and emotionally abusive. I left him but we are still married. I finally left him with my our 2 kids even though he threatened me to not sponsor me any longer and to have me deported if I didn't stay. My lawyer told me about VAWA, but to file a petitin I need proof of his citizenship. An dI don't have any copy of his previous Green Card or Certificate of NAturalization. How can I get a proof in order to be able to file my VAWA case? It's my only solution to be able to adjust my status. I did came legally but I overstayed because he told me to do so and that he would sponsor me.
Thanks for your help