What is the current state of the law on the interpretation of the Miranda Amendment?

Miranda advisements are required only when a person is subjected to "custodial interrogation." (Miranda, supra, 384 U.S. at p. 444.) "Interrogation" refers to both express questioning and to any words or actions that the police should know are reasonably likely to elicit an incriminating response from the suspect. (Rhode Island v. Innis (1980) 446 U.S. 291, 301 [100 S.Ct. 1682].) Simply telling a suspect why he has been arrested is not the functional equivalent of interrogation. (People v. Celestine (1992) 9 Cal.App.4th 1370, 1374.) An exception to the requirement of a Miranda advisement permits officers to ask questions reasonably related to obtaining the biographical data necessary for the administrative process of booking a person. (Pennsylvania v. Muniz (1990) 496 U.S. 582, 601-602 [110 S.Ct. 2638].) Volunteered statements also fall outside of the scope of Miranda. (Miranda, supra, 384 U.S. at p. 478.)

We review the trial court's implicit finding that Mims did not engage in custodial interrogation for substantial evidence or clear error. (People v. Bradford (1997) 14 Cal.4th 1005, 1034.)