Based on what the police asked for your ID?

The new law in AZ is to authorize police to ask for documents to prove the person is here legally without any cause (I might interpreter this wrong). This implies that, except AZ, under normal circumstances (i.e., you did not do anything illegal or suspicious), the police has NO　right to ask whether you are here legally or not. I am not sure about IL. You should talk to legal consultant in your school. If my understanding is correct, you might be able to complain police for racial profiling/discrimination.