In a recent decision, the United States Supreme Court ruled a suspect's words can be used against him if he fails to "clearly tell the police that he does not want to talk." 

The case in question involved a male suspect arrested in connection with a shooting, one year prior, outside a Michigan mall which killed one man and left another injured.  According to reports, the suspect was read his rights and verbally indicated he understood those rights but did not sign a waiver of rights form. 

During hours of subsequent interrogation, the suspect said very little; however, when asked "Do you pray to God to forgive you for shooting that boy down?", he responded "Yes."  While he refused to sign a confession or say anything further, he was later convicted of first-degree murder…due in no small part to this single word response. 

In rendering the majority opinion, Justice Kennedy said "[a suspect wishing to invoke his right to remain silent must] do so unambiguously."  Justice Sotomayor, though, strongly dissented, stating "[the ruling] turns Miranda upside down and marks a substantial retreat from the protection against self-incrimination."