A statement made by a criminal defendant during custodial interrogation by law enforcement officials is normally considered "testimonial" and the use of such a statement by a defendant in the defendant's criminal trial to prove the truth of the matter asserted by the defendant is therefore subject to the constraints imposed by the right of confrontation guaranteed to defendants in state and federal trials by the Sixth Amendment to the U.S. Constitution.

Cf. United States v. Roach, 590 F.2d 181, 185-186 (5th Cir. 1979) ("As to the necessity of a psychiatric examination, we have held that the district court has broad discretion in determining whether to order such examinations. United States v. Jackson, 576 F.2d 46 (5th Cir. 1978). Given the...It is possible that persons may be disqualified from serving as witnesses on grounds not expressly enumerated in codes of evidence or by general common law principles -- on unenumerated grounds such as age, illness, sensory defects, defects in intelligence, lack of understanding, inability to communicate, defects in memory, and inability to be truthful.

United States v. Cordoba, 104 F.3d 225, 227-228 (9th Cir. 1996) ("The per se Brown rule [Brown v. Darcy, 783 F.2d 1389, 1396 n.13 (9th Cir. 1986)] excluding unstipulated polygraph evidence is inconsistent with the 'flexible inquiry' assigned to the trial judge by Daubert. This is particularly evident...There is scattered federal authority that polygraph test results are admissible under some circumstances on the issue of the truthfulness or untruthfulness of a witness.

Cf. United States v. Luna, 21 F.3d 874, 881-882 (9th Cir. 1994) (reversing convictions for bank robbery because the trial court erred in admitting such evidence for the purpose of showing identity considering (1) "the various differences among the crimes;" (2) "the generic quality of the elements...Evidence of another crime, wrong, or act is not barred by the prohibition against circumstantial use of character if such other crime, wrong, or act is offered to prove identity.