If the police arrest a suspect and don't interrogate her, and if the suspect doesn't say anything, can the government use her silence against her at trial?
This scenario arose in a 2014 California case. The Golden State's highest court held that the prosecution can generally use, in its case in chief, silence that occurs after arrest, but before Miranda warnings and before interrogation if the suspect doesn't clearly invoke the privilege against self-incrimination.
(To learn about the admissibility evidence like this for "impeachment," see Miranda and Post-Arrest Silence. And for information about a defendant's silence before she has been arrested, but when she's being interrogated, see Invoking Your Right to Remain Silent.)
In the case in question (People v. Tom, S202107 (2014)), the defendant had caused a fatal car collision. The police took him into custody, but didn't ask him any questions. He didn't ask about the welfare of the other people involved in the accident. The California Supreme Court held that it could have been okay for the prosecution to present and argue to the jury that the defendant didn't ask about the victims.
The court held that, in order to prevent the prosecution from using his silence as part of its primary case under such circumstances, a defendant must clearly state to the police his intent to invoke the right to remain silent. (The court sent the case back to a lower court to determine whether the defendant had clearly invoked his privilege against self-incrimination—if he had, then evidence of his silence would have to be inadmissible.)
The California high court reasoned, in part, that a suspect might remain silent after arrest for any variety of reasons, and that his silence doesn't necessarily mean that he wishes to invoke the privilege against self-incrimination. So, in California cases like this, suspects must "clearly invoke" the privilege in a manner that "a reasonable police officer in the circumstances would understand."
Not all courts throughout the country agree with this holding. Other federal and state courts have held that the police may not use this kind of silence against suspects in this way.
In addition, the California Supreme Court indicated that there might be instances in which this kind of silence may be inadmissible in California courts—perhaps because the silence was too ambiguous to offer any legitimate proof and too likely to lead to unfair bias against the defendant. The court acknowledged the common perception of Miranda warnings and that defendants might subjectively intend to rely on the privilege against self-incrimination without saying anything. It suggested that much depends on the extent to which one would expect someone in a similar situation to say something.
The law on remaining silent can be complex, and it varies—as explained above. To understand how the law applies to your situation and for advice, consult a knowledgeable criminal defense lawyer.