Most people are familiar with the Miranda warnings. But police do not need to use these warnings every time they speak with a suspect. The Miranda decision only applies when a suspect undergoes "custodial interrogation". In other words, when a reasonable person would not feel that they were free to leave.
Most people are aware they have a Fifth Amendment privilege against self-incrimination when they are being questioned by law enforcement. What many people do not know, however, is that in some circumstances, the privilege must be expressly involved and, if it is not invoked, the failure to answer specific police questions can be used against them later. In those instances, silence is not golden and can be introduced as evidence of guilt at trial.