In what circumstances will a police officer be allowed to question a suspect in custody who had previously invoked his Miranda right?

In People v. Clark (1993) 5 Cal.4th 950, 22 Cal.Rptr.2d 689, 857 P.2d 1099, the defendant was being transported to the hospital by the police to obtain a blood sample. He had previously invoked his Miranda rights. He asked the officers what the penalty was for the murder for which he was under arrest, stating: "`What can someone get for something like this, thirty years?'" (Id. at p. 982, 22 Cal.Rptr.2d 689, 857 P.2d 1099.) The officer responded that he had never seen anyone serve more than seven and a half years unless the person was a "`mass murderer.'" Following this exchange, the defendant confessed. (Ibid.) We held that this conversation did not constitute an interrogation: "Clearly, not all conversation between an officer and a suspect constitutes interrogation. The police may speak to a suspect in custody as long as the speech would not reasonably be construed as calling for an incriminating response." (Id. at p. 985, 22 Cal.Rptr.2d 689, 857 P.2d 1099.) We concluded: "The record does not establish that defendant was subject to `compelling influences, psychological ploys, or direct questioning.' [Citation.]" (Id. at p. 986, 22 Cal.Rptr.2d 689, 857 P.2d 1099.)