The Miranda rule applies to the use of testimonial evidence in criminal proceedings that is the product of custodial police interrogation.[3] Therefore, for Miranda to apply six factors must be present: (1) evidence must have been gathered (2) the evidence must be testimonial[4] (3) the evidence must have been obtained while the suspect was in custody[5] (4) the evidence must have been the product of interrogation [6](5) the interrogation must have been conducted by state-agents[7] and (6) the evidence must be offered by the state during a criminal prosecution. [8]
The first requirement is obvious. If the suspect did not make a statement during the interrogation the fact that he was not advised of his Miranda rights is of no import. Second, Miranda applies only to “testimonial” evidence as that term is defined under the Fifth Amendment.[9] For purposes of the Fifth Amendment, testimonial statements mean communications that explicitly or implicitly relate a factual assertion [an assertion of fact or belief] or disclose information.[10][11] The Miranda rule does not prohibit compelling a person to engage in conduct that is incriminating or may produce incriminating evidence.
Thus, requiring a suspect to participate in identification procedures such as giving handwriting[12] or voice exemplars, fingerprints, DNA samples, hair samples, and dental impressions is not within the Miranda rule. Such physical or real evidence is non-testimonial and not protected by the Fifth Amendment self-incrimination clause. [13]On the other hand, certain non-verbal conduct may be testimonial. For example, if the suspect nodded his head up and down in response to the question "did you kill the victim" the conduct is testimonial, it is the same as saying "yes I did" and Miranda would apply.[14]
Third, the evidence must have been obtained while the suspect was in custody.[15] Custody means either that the suspect was under arrest or that his freedom of movement was restrained to an extent “associated with a formal arrest.”[16] A formal arrest occurs when an officer, with the intent to make an arrest, takes a person into custody by the use of physical force or the person submits to the control of an officer who has indicated his intention to arrest the person. Absent a formal arrest, the issue is whether a reasonable person in the suspect’s position would have believed that he was under arrest.[17] Applying this objective test, the Court has held Miranda does not apply to roadside questioning of a stopped motorist or to questioning of a person briefly detained on the street - a Terry stop.[18] Even though neither the motorist nor the pedestrian is free to leave, this interference with the freedom of action is not considered custody for purposes of the Fifth Amendment. Berkemer v. McCarty. The court has similarly held that a person who voluntarily comes to the police station for purposes of questioning is not in custody and thus not entitled to Miranda warnings particularly when the police advise the suspect that he is not under arrest and free to leave. Generally, incarceration or imprisonment constitutes custody.
http://en.wikipedia.org/wiki/Miranda_v._Arizona
