When a prosecutor manipulates the array of evidence before the grand jury, does the prosecutor have a duty to inform the jury of exculpatory evidence of which he or she is aware of?

accused of crime before the grand jury, which is to say that it is a "constitutional right;" any prosecutorial manipulation which substantially impairs the grand jury's ability to reject charges which it may believe unfounded is an invasion of the defendant's constitutional right .... When the prosecutor manipulates the array of evidence to the point of depriving the grand jury of independence and impartiality, the courts should not hesitate to vindicate the demands of due process.' " ( Ibid. ) Referring to its decision in that case, Johnson v. Superior Court (1975) 15 Cal.3d 248, 124 Cal.Rptr. 32, 539 P.2d 792, which held that a prosecutor has a duty to reveal to the grand jury the existence of exculpatory evidence of which he or she is aware,⁷ the court reasoned, "If the grand jury cannot fulfill its obligation to act independently and to protect citizens from unfounded obligations [citation] when not advised of relevant exculpatory evidence, neither can it do so if it is invited to indict on the basis of incompetent and irrelevant evidence." ( Backus , at p. 393, 152 Cal.Rptr. 710, 590 P.2d 837.) It held that "when the extent of incompetent and

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