Miranda warnings inform people of their constitutional rights to remain silent and to have a lawyer present during police questioning. Police read Miranda rights after detaining someone but before beginning an interrogation (questioning).
Police must inform arrestees of the following Miranda rights:
The police don't have to say the warnings in that exact way or order. They just need to convey these rights to an accused person.
The rights included in the Miranda warnings come from the Fifth and Sixth Amendments to the Constitution. The Fifth Amendment contains the privilege against self-incrimination, and the Sixth Amendment contains the right to counsel. The name Miranda comes from a 1966 Supreme Court case Miranda v. Arizona, 384 U.S. 436.
Miranda applies only to "custodial interrogations," which means the police don't have to give Miranda warnings every time they question or talk to someone.
Miranda rights come into play when the police arrest or detain someone—this is the "custodial" part. Detention here means that the person reasonably believes they are not free to leave. Handcuffs are a good indicator that a person is being detained, but detention can occur in less obvious ways. If police are blocking a person's exit and telling that person to "stay put," that person is not free to leave. It doesn't matter where the questioning happens—at the police station, the scene of the crime, or a busy public place. What matters is that the person is in custody and cannot leave.
Police must also do the questioning—this is the "interrogation" part. If a person is sitting in the back of a cop car and starts rambling on about the crime, police don't need to advise the person of their Miranda rights because there's no interrogation. Anything that person says is fair game.
For instance, say Melody encounters the police at a house that has been set on fire. The police begin to question her about what she saw. Because they're questioning her as a witness and have not restrained her movement in any way, they're not required to give her Miranda warnings. However, during the questioning, Melody mentions a detail that the police don't believe she could have known without being involved in the fire. They then arrest her on suspicion of arson and inform her of her Miranda rights. The police can use as evidence anything she said before they gave her the Miranda warning and anything she chose to say after.
To invoke your Miranda rights (even the right to remain silent), you must say something to police that indicates you are choosing to remain silent and want the interrogation to end or that you want an attorney. Staying quiet in the face of the questioning is not enough to invoke Miranda or to make the interrogation stop. On the other hand, if a person answers questions after being given Miranda warnings, courts consider the person to have knowingly waived (given up) their Miranda rights.
Invoking Miranda rights isn't a one-time deal. A person may invoke Miranda rights at any time during the interrogation, even after answering some questions. Upon invoking Miranda, the interrogation must end.
Let's say the police arrested Joe on suspicion of burglary and read him his Miranda rights. Joe continues to answer questions about an associate, Charlie. After thirty minutes of questioning, Joe realizes that he might be incriminating himself, along with Charlie, so he asks for an attorney. The interrogation must stop until Joe has consulted with an attorney.
Voluntary statements made after an arrest but before questioning and giving Miranda warnings are still admissible as evidence. If the police arrest Charlie on suspicion of burglary and while transporting him to the station for questioning he shouts out, "Joe has my burglary tools!"—this statement can be used against him because he said it voluntarily before questioning had begun.
Once questioning begins, if the police fail to advise a person of their Miranda rights, the person's statements cannot be used at trial. Failure to give a Miranda warning doesn't mean all charges will be dropped. Instead, the prosecution cannot use evidence obtained in violation of the Miranda rule at trial to prove the person's guilt. (The statements, however, can be used to contradict testimony given by the defendant at trial and sometimes at sentencing.)
If you've been arrested and face interrogation by the police, it's important to ask for a lawyer before answering any questions. An experienced defense attorney can help you understand the charges and advise you during police questioning so that your rights are protected.