If the FBI, DEA, Secret Service or Homeland Security come to talk to you about something you may have done, beware. First, no matter how friendly or cordial the agents may be, this is not a social visit. They are there for one reason only: to gather evidence for a potential criminal indictment. If the target is you, whether they say so or not, it is in your best interest NOT to cooperate with them. This should be done respectfully, but firmly. For example, “Agent, I choose not to speak with you at this time. I also choose to have my attorney present and exercise my rights under the 6th Amendment to the U.S. Constitution.” The U.S. Supreme Court has made it very clear that your choice of language is vitally important. The phrasing above is based on several opinions by the Supreme Court as to how to invoke both your right to remain silent and your right to counsel.
Also, remember that it is perfectly permissible for these agents to lie or mislead you while conducting this “interview.” Doing so will not get them in trouble with either the court. You should be very careful and use caution when dealing with law enforcement.