Under what condition is a suspect considered to be in custody for Miranda purposes?

A suspect is considered to be in custody for Miranda purposes when they are formally arrested or restrained. This means that the individual’s freedom of movement is significantly limited, and they are not free to leave. The underlying principle is to protect a suspect’s Fifth Amendment right against self-incrimination.

In this context, formal arrest or restraint indicates that law enforcement has a degree of control over the suspect's movements, which triggers the obligation to inform them of their rights. This is critical because, when someone is in custody, any statements made during interrogation without the provision of Miranda warnings may be inadmissible in court.

While questioning the suspect is relevant, the interrogation must occur under conditions where the suspect is not free to leave, which is captured by the definition of being in custody. Simply being at home does not equate to custody, nor does it when a suspect is taken to jail unless they have been formally arrested or are under restraint before that point. Thus, the core condition for custody is the formal arrest or restraint that limits the suspect's freedom.