Using the Fifth Amendment
The Fifth Amendment provides that “No person … shall be compelled in any criminal case to be a witness against himself.” “Criminal case” includes preliminary hearings, grand jury hearings, all pre-trial hearings, trial and sentencing.
The privilege has a broad scope. It extends not only to answers that would in themselves support a conviction, but also to answers that would furnish a link in the chain of evidence needed to prosecute. The privilege applies when it is evident from the implications of the question, in the setting in which it is asked, that a responsive answer to the question or an explanation of why it cannot be answered might be dangerous because injurious disclosure could result.
Thus, you can decline to answer a prosecutor’s questions at any criminal hearing on the grounds that the answer may incriminate you, or may provide a link in a chain of inferences that might tend to prove your guilt of a criminal charge. Even the innocent may invoke the privilege if there is reasonable cause to fear prosecution.
No adverse inferences may be drawn
No adverse inferences may be drawn from the exercise of the privilege because doing so would penalize its exercise. Thus, a prosecutor may not comment on a defendant’s exercise of the privilege and the court must instruct the jury that it cannot draw any adverse inference from a defendant’s choice not to testify.
To the extent possible, a criminal trial jury should not learn that the defendant exercised the privilege outside the courtroom or in another legal proceeding, such as before the grand jury. For example, a defendant could not be cross-examined at trial on his invocation of the Fifth Amendment in grand jury testimony.
Civil or administrative proceedings
You may assert the privilege at civil or administrative proceedings in which you reasonably believe that the information sought, or discoverable as a result of your testimony, could be used in a subsequent state or federal criminal proceeding.
This means that you cannot be threatened with contempt for your refusal to answer and that your assertion of the privilege cannot be used against you in a later criminal proceeding. However, an inference can be drawn against you in the civil proceeding.
Furthermore, the prosecution cannot introduce in the criminal case your assertion of the privilege in the civil proceeding, even to cross-examine you.
Even if you choose to testify before a grand jury, at earlier proceedings in the case, or at a related civil proceeding, you may still assert the privilege at your criminal trial. However, the prosecution can introduce your earlier testimony unless it was given under a grant of immunity. Thus, when criminal proceedings are on the horizon, you should avoid testifying or personally answering discovery at a civil proceeding that touches on the same issues.