Yeah, that's why the people doing the study to investigate illegal voting should focus on California and New York. Start there and see what you find. For now I would call it a study, rather than an "investigation". The investigation starts with a study, comparing voter registrations to E-Verify or perhaps other databases the feds or states have and then when you find a no match, investigate further, then if it's clear the are non-citizens, then compare that list to the voting list. It's very easy. Maybe a little time consuming, but with electronics, it shouldn't take long to find out who voted illegally.