What is the current state of the law on whether a suspect was in custody for Miranda purposes?

(Oregon v. Elstad (1985) 470 U.S. 298, 306-307.) "Consequently, unwarned statements that are otherwise voluntary within the meaning of the Fifth Amendment must nevertheless be excluded from evidence under Miranda." (Id. at p. 307.)

An appellate court's determination of whether a suspect was in custody for Miranda purposes is a mixed question of fact and law. (See People v. Cromer (2001) 24 Cal.4th 889, 894-895.) Mixed questions of fact and law that implicate constitutional rights are subject to independent review, but reviewing courts apply a deferential standard of review to the trial court's findings of fact. (Ibid.)