Generally, an individual has right to remain silent, and his or her exercise of that right cannot be used against him in a court of law. However, some courts have found that in some circumstances, the government may be allowed to introduce a suspect’s silence as evidence of guilt. The Court of Criminal Appeals of Texas has held in Salinas v. Texas* that Mr. Salinas’ refusal to answer certain questions in a pre-arrest, pre-Miranda interview were not protected by the Fifth Amendment. You can read all the documents at SCOTUSblog.
The courts have previously determined that if someone is formally placed under arrest (or if they are informed of their rights), their Fifth Amendment protections would be preserved. Crimcourts has some concern that if someone’s silence can be used against them, regardless at what stage of a proceeding, then they are almost compelled to talk. That is, the suspect is given a choice to answer, or to have that silence used against them at trial. If they are to be punished for being silent, their testimony is compelled to some degree. Different courts have ruled differently on the issue, and the resulting conflict in the law was likely a prompt for the U.S. Supreme Court to accept the case to review and rule definitively on the issue.
*Salinas v. Texas, 369 S.W.3d 176 (Tex. Crim. App. 2012). http://www2.bloomberglaw.com/desktop/public/document/Salinas_v_State_369_SW3d_176_Tex_Crim_App_2012_Court_Opinion