In terms of law enforcement, some places require that you provide identification of who you are to law enforcement on request or it can be a misdemeanor charge. Lying to FBI (or many fed law enforcement agents) is a felony under federal law. Beyond that I would say only "I don't answer those questions" to everything they ask and direct them to ask my lawyer instead. If you do not have a lawyer, find the local lawyer who tends to win all of the cases in court for police brutality, etc. and seems to have a personal vendetta against the police. Usually one in every decent sized locale. The local cops anyway will generally hate having to deal with that lawyer and find it not worth their time and unless they have significant reason may find the investigation not worth the hassle for them. Even if he is not actually your lawyer, "I don't answer those questions" and "talk to my lawyer Mr. XXX". Make your lawyer alone answer all questions they ask for you as if he was your translator. Unless they are charging/arresting someone, usually don't have to go to the trouble of hiring a lawyer.

In terms of law enforcement, some places require that you provide identification of who you are to law enforcement on request or it can be a misdemeanor charge. Lying to FBI (or many fed law enforcement agents) is a felony under federal law. Beyond that I would say only "I don't answer those questions" to everything they ask and direct them to ask my lawyer instead. If you do not have a lawyer, find the local lawyer who tends to win all of the cases in court for police brutality, etc. and seems to have a personal vendetta against the police. Usually one in every decent sized locale. The local cops anyway will generally hate having to deal with that lawyer and find it not worth their time and unless they have significant reason may find the investigation not worth the hassle for them. Even if he is not actually your lawyer, "I don't answer those questions" and "talk to my lawyer Mr. XXX". Unless they are charging/arresting someone, usually don't have to go to the trouble of hiring a lawyer.