I petitioned for my spouse from Nigeria. He came on a spousal visa in February 2020. In 2022, I discovered many things including a fake divorce decree that he provided to USCIS when I petitioned for him. He is still married in Nigeria. He applied for N-400 unbeknownst to me and got it in 2023 and left the marriage. After lying about his whereabouts, I discovered he’s in Nigeria with wife and their child. Divorce decree has been confirmed that it is counterfeit. What are my next steps.