FBI

When the FBI is undertaking an investigation they can always refuse to answer questions using the reason that it is an ongoing investigation. Then they can selectively leak information that will strengthen their position when it comes to getting an indictment by the grand jury. This is normal operating procedure. They have the entire law enforcement power of the federal government and they can leak to help their cause. They can also lie to you during an interrogation but you best not lie to them. If you are falsely accused you may go broke paying legal fees and in the end if you are found not guilty then you are just out that money. You can then attempt to sue for false arrest but you better get prepared for more legal fees. They have unlimited time and resources and can drag out a case.