Under what condition must the Miranda warning be read to a suspect?

The Miranda warning must be read to a suspect when they are in custody and being questioned. This requirement arises from the Supreme Court case Miranda v. Arizona, which established that individuals taken into custody must be informed of their rights to remain silent and to have an attorney present during questioning. The rationale behind this is to protect the Fifth Amendment right against self-incrimination and to ensure that suspects are aware of their legal rights when they are in a potentially coercive environment.

In this context, "in custody" refers to situations where a reasonable person would feel they are not free to leave, which establishes the necessity for the warnings to prevent involuntary confessions or statements that might be made under duress. When questioning occurs under these circumstances, the absence of the Miranda warning can lead to any statements made by the suspect being inadmissible in court.

Understanding this condition is crucial for law enforcement officers as it directly impacts the legality of the interrogation process and the rights of individuals under arrest.