When police officers make an arrest, they commonly interrogate (question) the arrestee. Usually they are trying to strengthen the prosecution’s case by getting the arrestee to provide evidence of guilt. An interrogation may have other purposes as well, such as developing leads to additional suspects.
(For information on ending an interrogation, see Miranda Rights: Cutting Off Police Questioning.)
By voluntarily answering police questions after arrest, a suspect gives up two rights granted by the U.S. Constitution:
Although people are entitled to voluntarily give up these and other rights, the courts have long recognized that voluntariness depends on knowledge and free will, and that people questioned by the police while they are in custody frequently have neither.
To remedy this situation, the U.S. Supreme Court ruled in the case of Miranda v. Arizona (1966) that information obtained by police officers through the questioning of a suspect in police custody may be admitted as evidence at trial only if the questioning was preceded by certain cautions known collectively as a “Miranda warning.” Accordingly, police officers usually begin their questioning of a person in custody by first making the following statements:
If a suspect is in police custody, it doesn’t matter whether the interrogation takes place in a jail or at the scene of a crime, on a busy downtown street, or in the middle of an open field. Other than routine automobile stops and brief on-the-street detentions, once a police officer deprives a suspect of freedom of action in any way, the suspect is in police custody and Miranda is activated.