From the article and multiple police investigations it sounds like your software is used by them to run their illicit businesses. Having users register could be one option. If there's one guy and a bunch of teenage girls on a plan that might be a red flag or worth further review. Perhaps your company could look at all the people that were busted and see if there's commonalities with how they use the app. It's my guess that if multiple people were using it for trafficking and were busted there's probably traffickers using your software right now.