You have the right to remain silent. Anything you posted on Facebook can and will be used against you in a court of law. You have the right to an attorney, unless he uses Facebook too, then you better have one appointed to you.
Did you know that what you say on Facebook can be used against you in a court of law? If you're sharing something with your friends, you may as well be sharing directly with the judge and jury: A recent ruling in a U.S. federal court says that if you post something on Facebook, your friend can share that information with the police — it's not a violation of your privacy.