I also wouldn't answer any questions. If you're being detained and questioned by law enforcement, you have a right to have an attorney present. And to be charged with a crime within a certain timeframe, for that matter. If there's none of that, hey by golly you must not be under arrest and this isn't a legal proceeding. Answer every question by reminding them you're a US citizen. Maybe repeat your social security number dramatically as if you're a POW in the hands of a foreign power. (Certainly you're in the hands of some traitors against the USA, so it's not a huge stretch.)