In the Miranda v. Arizona case in 1966, the U.S. Supreme Court ruled that the police must give suspects specific warnings prior to custodial interrogations, notes Brooks Holland for the American Bar Association. The court ruled that the police must inform a suspect of his right to remain silent and his right to an attorney, and must tell him he will be provided with an attorney if he cannot afford one and what he says can be used against him.
The Miranda v. Arizona Supreme Court decision was based on the facts in four different cases in which the same legal issues surrounding interrogations had arisen, states Holland. In the Miranda case specifically, police in Arizona arrested Ernesto Miranda in 1963, and the suspect, who had been isolated in a room with just the police present, signed a confession and was convicted in court. The U.S. Supreme Court overturned Miranda's conviction and ruled that to prevent coercion, the police must take a proactive role in ensuring suspects know their rights.
The Miranda v. Arizona ruling applies only during custodial interrogations during which people have been significantly deprived of their freedoms, such as after arrests, according to Holland. The police do not have to warn people of their rights if they are not in custody, and prosecutors may use confessions that suspects offer up voluntarily.