Mostly, no. You are generally not required to answer FBI or police questions (except, e.g., if you are asked for identification while driving a vehicle).
Yes. You have a right to talk to an attorney. If an FBI agent or police officer asks to speak to you, tell him or her that you want to consult with an attorney first. If you want to talk to the FBI or police, your attorney can respond on your behalf to set up an interview.
Yes. ANY information you give to an officer without an attorney, even if it seems harmless, can be used against you or someone else. Lying to a federal officer is a crime. Remaining silent is NOT a crime (except in limited situations when you can be required to identify yourself).
You are NOT required to allow the officer into your home without a warrant. Ask to see the warrant. If the officer does not have one, you do not have to let him/her into your home. However, do not try to stop him/her if he forces his way into your home or office. Simply state that they do not have your permission to enter.
Yes. If the officer says that they have a warrant for your arrest, you have a right to see the warrant. You must go with the officer, but you do not have to answer questions until you consult an attorney.
If you are detained, you should ask for an attorney and remain silent.
Learn about your rights at the airport here.
Questioned by the FBI or police?
This is a letter to persons who believe they might be contacted by their employer, a funder, or government officials regarding their relationship to the People’s Republic of China. This includes, for example, university professors who have received grants to support their academic activities; researchers in STEM fields working in the private sector; civil servants; and even U.S. military personnel. It also includes individuals regardless of citizenship; holding a green card, having naturalized, or even being a native-born citizen will not protect you from potential problems. The most important message here is: if you have any concerns at all, you should consult with a lawyer as soon as possible, preferably one with specialized expertise.