Can the police conduct post-examination questioning on a defendant who has waived his Miranda right?

But even assuming a custodial interrogation, defendant validly waived his Miranda rights and the police could constitutionally conduct postexamination questioning "unless the circumstances changed so seriously that his answers no longer were voluntary, or unless he was no longer making a 'knowing and intelligent relinquishment or [755 P.2d 986] abandonment' of his rights." (Wyrick v. Fields (1982) 459 U.S. 42, 47, 103 S.Ct. 394, 396, 74 L.Ed.2d 214.)

Page 536