How to report immigration fraud
My cousin recently passed roughly two months ago in a fatal car accident. To my family's surprise, we found out that he was married and had been married for (according to his wife) approximately 3 years. Since my cousin was very close to us; as his family, we feel that if this was a legitimate marriage, we would have known of it. Furthermore, if this was a legitimate marriage, he would have lived with his wife and not in a separate home that he shared with his sister since 2000. To make a long story short, the wife wants to claim all of his assets. While we acknowledge that legally she is entitled to all of his wealth, he left a daughter (from another woman) behind and we want to make sure that she (the daughter) inherits some of her beloved father's wealth. The wife has made the past few weeks a living hell for our family. His mother is a retired 70 year-old woman and the wife has not even offered her condolences to my aunt. The only thing the wife seems concerned about is my dead cousin's money! She cleaned out the house that he lived in with his sister and now she's hired a lawyer to send my family threatening letters regarding withholding monies from his rental properties that she claims we have!
So now that she's stooped so low, we want to play dirty with dirty. We have reason to believe that my cousin may have filed divorce papers and was in the process of getting a divorce from this woman since she has attained her green card. Thus my question is, "HOW DO WE GO ABOUT REPORTING THIS FRAUDULENT MARRIAGE TO IMMIGRATION?" and at this point, what effect, if any, will this have have on her immigration status?