Under Miranda v. Arizona, before a suspect who is in the custody of the police can be questioned the police must read him or her Miranda rights. This includes a right to remain silent and the right to the presence of an attorney during questioning.

Now that we know that the second man suspected of the killing and mayhem at the Boston Marathon is likely going to live, questions have been raised about whether he is entitled to Miranda rights. Must Dzhokhar Tsarnaev be informed of the right to remain silent? If so, when?

First of all, it is a common misconception that an individual must be read Miranda rights when arrested. Although police officers on TV read Miranda rights the moment handcuffs are slapped on, they don’t have to. Miranda warnings must only be given when a suspect is in custody and the police are going to question him. Here, the question is whether the police must advise Dzhokhar Tsarnaev of his rights under Miranda v. Arizona before they start to question him. The answer is yes.

I have heard some commentators assert that the “public safety exception” exempt the FBI from reading Miranda rights to the Boston Marathon bomber. Not true. The public safety exception was created by the Supreme Court in New York v. Quarles. In that case, a woman flagged down the police and told them she’d just been raped. She described the suspect, said he had a gun, and that he had just entered the A&P. The officers ran into the supermarket and found an individual fitting the description of the suspect she described. He had a holster, but did not have a gun. An officer demanded to know what he did with the possibly-loaded weapon. In that case, the “exigency” of protecting the public against a rapidly-escalating violent situation trumped Miranda rights. The officer was entitled to question the suspect “on the scene” in order to preserve public safety.

In this case, one suspect is dead. The other is gravely wounded and hospitalized. Boston is – no longer under – lock down. The exigency has passed.

To be sure, the authorities want to question the one living suspect. They want to find out why he and his brother committed such a heinous act in order to have the intelligence to prevent future acts of terrorism. But there is no longer an immediate risk of danger.

The remedy if a court finds that Miranda warnings were required but the FBI questions a suspect without Miranda warnings is that the suspect’s statement gets suppressed, meaning that it can’t be used as evidence in his criminal case. It can be used in other contexts. The FBI and DOJ may decide that they already have overwhelming evidence of Mr. Tsarnaev’s guilt. They might make a calculated decision to question him without Miranda warnings, knowing that even if his statement cannot be admitted as evidence in his criminal prosecution, it is valuable to law enforcement.