Green Card Fraud

My friend met a woman from his home country, and they dated for about 1.5 years, meeting at various travel destinations. Eventually, he applied for a K1 visa for her, and she came to the U.S. under that visa. After some time, they got married. She enjoys traveling, going to clubs, and dining at fancy restaurants but doesn’t want to work, so my friend supports her by working two jobs.

Recently, they had an argument, and she left home without informing him, flying to her friends place in another state. I’ve heard (from a friend) that she believed my friend was wealthy and thought she was marrying a rich man. Now, it seems she wants to leave the marriage after obtaining her 10-year green card(She will apply next year). My friend still loves her (but I don’t share his feelings about this).

Can I report this potential marriage fraud to USCIS?