Be Careful when Speaking to Federal Agents - 18 U.S.C. Section 1001
The most important paragraph if you're not interested in reading the whole thing:Is there an intelligent alternative to lying or telling the truth that we have not yet examined? Yes. In our hypothetical interview, you can politely decline to be interviewed by the FBI agent. Tell the agent that you have an attorney and that "my attorney will be in contact with you." If the agent persists, say that you will not discuss anything without first consulting counsel. Ask for the agent's card, to give to your attorney. If you have not yet hired a lawyer, tell the agent that "I want to consult a lawyer first" or that "an attorney will be in touch with you." The absolutely essential thing to keep in mind is to say nothing of substance about the matter under investigation. It is preferable to do this by politely declining to be interviewed in the absence of counsel. If the agent asks "why do you need an attorney?" or "what do you have to hide?" do not take his bait and directly respond to such questions. (Do not even say that you have nothing to hide.) Simply state that you will not discuss the matter at all without first consulting counsel and that counsel will be in touch with him. If the agent asks for a commitment from you to speak with him after you have consulted or retained counsel, do not oblige him. Just respond that you will consult with your attorney (or "an" attorney) and that the attorney will be in touch. And by all means do not get bullied or panicked into making up a phony reason for refusing to talk. You are not obliged to explain your decision to anyone.