Salinas v. Texas

Salinas (defendant) voluntarily went to a police station, was not in custody, and answered questions about a murder without receiving Miranda warnings, but fell silent -- looking down, shuffling his feet, biting his lip, and clenching his hands -- when asked whether his shotgun would match shells found at the murder scene. At his later murder trial, the prosecution used his silent, physical reaction to that question as evidence of guilt; Salinas argued this violated his Fifth Amendment privilege against self-incrimination, and after losing at the state level, the Supreme Court granted certiorari.