California law provides that a defendant has a due process right not to be indicted in the absence of a determination of probable cause by a grand jury acting independently and impartially in its protective role. (Greenberg, supra, 19 Cal. 2d 320; Parks v. Superior Court, supra, 38 Cal. 2d at p. 611; Cal. Const., art. I, 14; Johnson, supra, 15 Cal. 3d at p. 253; Backus, supra, 23 Cal. 3d at p. 393; Cummiskey, supra, 3 Cal. 4th at p. 1022, fn. 1.) An indicted defendant is entitled to enforce this right through means of a challenge under section 995 to the probable cause determination underlying the indictment, based on the nature and extent of the evidence and the manner in which the proceedings were conducted by the district attorney. (Backus, supra, 23 Cal. 3d at p. 393; Cummiskey, supra, 3 Cal. 4th at p. 1022, fn. 1.) In reviewing the merits of such a challenge, courts have routinely considered relevant nontestimonial portions of the record of the grand jury proceedings. Section 995 provides statutory authority for challenging an indictment. That section provides, in pertinent part, that "(a) . . . the indictment . . . shall be set aside by the court in which the defendant is arraigned, upon his or her motion, in either of the following cases: (1) . . . (A) Where it is not found, endorsed, and presented as prescribed in this code. (B) That the defendant has been indicted without reasonable or probable cause." the second ground regarding reasonable or probable cause was added to the code in 1949. (Stats. 1949, ch. 1311, 1, p. 2299.) Prior to that, the only grounds available to set aside an indictment were if the indictment was not "found, endorsed, and presented as prescribed in this code." This subdivision refers to defects appearing on the face of the indictment. ( People v. Jefferson (1956) 47 Cal. 2d 438, 442 [303 P.2d 1024].) Section 940 provides that "An indictment cannot be found without concurrence of at least 14 grand jurors in a county in which the required number of members of the grand jury prescribed in Section 888.2 is 23, at least eight grand jurors in a county in which the required number of members is 11, and at least 12 grand jurors in all other counties. When so found it shall be endorsed 'A true bill', and the endorsement shall be signed by the foreman of the grand jury." (Italics added.) Section 943 provides, "when an indictment is found, the names of the witnesses examined before the Grand Jury, or whose depositions may have been read before them, must be inserted at the foot of the indictment, or indorsed [sic] thereon, before it is presented to the Court." Section 944 provides, "An indictment, when found by the grand jury, must be presented by their foreman, in their presence, to the court, and must be filed with the clerk." (Italics added.) It has been held that " 'The presenting of the indictment, endorsed as a true bill by its foreman to the court by the grand jury in its own presence, indicates the regularity of all the prior proceedings of that body in the matter.' " ( People v. Yu (1983) 143 Cal. App. 3d 358, 373 [191 Cal. Rptr. 859], quoting People v. Tennant (1939) 32 Cal. App. 2d 1, 9 [88 P.2d 937].) The 1949 amendment to section 995 adding the "reasonable or probable cause" ground was in response to the Supreme Court's opinion in Greenberg v. Superior Court (Greenberg) (1942) 19 Cal. 2d 319 [121 P.2d 713]. In Greenberg, the defendant sought to overturn an indictment on the basis that there was no evidence presented to the grand jury of his guilt of the offense charged. The respondent court denied relief and set the case for trial, finding that California law did not provide a basis to restrain a court from proceeding with a trial on the ground of a lack of evidence of guilt presented to the grand jury. The Supreme Court disagreed, finding that an indictment, like an information, must be supported by reasonable or probable cause. "A grand jury that indicts a person when no evidence has been presented to connect him with the commission of the crime charged, exceeds the authority conferred upon it by the Constitution and laws of the State of California and encroaches upon the right of a person to be free from prosecution for crime unless there is some rational ground for assuming the possibility that he is guilty." (Id. at p. 322.) The court in Greenberg explained that "at common law an indictment returned by a grand jury was unimpeachable because the grand jury proceedings were clothed in secrecy and a court had no access to the evidence upon which the indictment was based. There ceased to be any reason for the common law rule in this state, however, when section 925 of the Penal Code was amended to require that a transcript, available to both defendant and prosecutor, be kept of the testimony introduced before the grand jury in all criminal causes where an indictment is returned." (Greenberg, supra, 19 Cal. 2d at p. 322.) The court concluded that the grand jury had exceeded its authority by returning an indictment unsupported by evidence. Such an indictment was void and conferred no jurisdiction upon the superior court to proceed with the trial. (Ibid.) Following Greenberg, courts recognized that the California Constitution "protects a person from prosecution in the absence of a prior determination by either a magistrate or a grand jury that such action is justified." (Parks v. Superior Court (1952) 38 Cal. 2d 609, 611 [241 P.2d 521], italics added; Cal. Const., art. I, former 8 [now 14].) The phrase "reasonable or probable cause" in section 995 has been defined as a determination that " ' " 'a public offense has been committed, and there is sufficient cause to believe the defendant guilty thereof." (Cummiskey v. Superior Court, supra, 3 Cal. 4th at pp. 1026-1027, quoting Lorenson v. Superior Court (1950) 35 Cal. 2d 49, 56 [216 P.2d 859].) In other words, to find probable cause to indict, "the grand jury must determine whether sufficient evidence has been presented to support holding a defendant to answer on a criminal complaint." (Cummiskey v. Superior Court, supra, 3 Cal. 4th at p. 1027.) Following the 1949 amendment to section 995, it became commonplace for indicted defendants to bring a motion under that section to set aside the indictment on grounds that the transcript showed there was insufficient evidence for the grand jury to find probable cause. (See, e.g., Buck v. Superior Court (1966) 245 Cal. App. 2d 431, 433-434 [54 Cal. Rptr. 282].) In Johnson v. Superior Court, supra, 15 Cal. 3d 248 (Johnson), the Supreme Court established a new ground for dismissal of the indictment: the prosecutor's failure to advise the grand jury of the possible existence of exculpatory evidence. The receipt and consideration of exculpatory evidence was governed by section 939.7, which provides as follows: "The grand jury is not required to hear evidence for the defendant, but it shall weigh all the evidence submitted to it, and when it has reason to believe that other evidence within its reach will explain away the charge, it shall order the evidence to be produced, and for that purpose may require the district attorney to issue process for the witnesses." The court in Johnson ruled that when the district attorney was aware of exculpatory evidence, he or she was obligated under section 939.7 "to inform the grand jury of its nature and existence, so that the grand jury may exercise its power under the statute to order the evidence produced." ( Johnson, supra, 15 Cal. 3d at p. 255.) Failure to do so, the court ruled, could result in dismissal of the indictment. (Ibid.) The court in Johnson emphasized the grand jury's protective role " 'to stand between the prosecutor and the accused, and to determine whether the charge was founded upon credible testimony . . . .' " ( Johnson, supra, 15 Cal. 3d at p. 253, quoting Hale v. Henkel (1906) 201 U.S. 43, 59 [26 S. Ct. 370, 372, 50 L. Ed. 652].) Although the grand jury was duty bound under section 939.7 to weigh all the evidence and to order exculpatory evidence if it had reason to believe such evidence would explain away the charges, the court recognized that the grand jury would ordinarily have no reason to know of the existence of any such evidence unless the district attorney so informed them. The People had argued in Johnson that section 939.7 placed the impetus for obtaining exculpatory evidence solely in the hands of the grand jury itself and that the district attorney had no duty to produce evidence unless the jury called for it. The Johnson court rejected this argument, explaining that because the grand jury process was not an adversarial proceeding, the district attorney was obligated to inform the grand jury of exculpatory evidence they might not otherwise be aware of. The People's limited construction of section 939.7 would thwart the ability of the grand jury to "weigh all the evidence" and would thereby "nullify its protective role." ( Johnson, supra, 15 Cal. 3d at p. 254.) The holding of the majority in Johnson was based on statutory grounds, namely the court's interpretation of section 939.7. the majority declined to consider the petitioner's due process arguments. However, three justices wrote separately, expressing concern that the grand jury indictment process was constitutionally inadequate. ( Johnson, supra, 15 Cal. 3d 248 (conc. opns. of Mosk, J., Wright, C. J., and Tobriner, J.).) Several years later, in Hawkins v. Superior Court (1978) 22 Cal. 3d 584 [150 Cal. Rptr. 435, 586 P.2d 916], a newly formed majority of the court held that a defendant who is prosecuted by indictment is denied equal protection under the California Constitution unless he or she is provided a preliminary hearing and the concomitant rights which attach when prosecution is by information. Hawkins was in turn abrogated by a ballot initiative (Prop. 115, the Crime Victims Justice Reform Act, passed June 5, 1990) adding section 14.1 to article I of the Constitution. Section 14.1 now provides "If a felony is prosecuted by indictment, there shall be no postindictment preliminary hearing." After the rule announced by the court in Johnson, indicted defendants could challenge an indictment by a motion under sections 995 and 939.7 on grounds that could necessitate the disclosure of nontestimonial portions of the record of the proceedings. It appears from the opinions in cases considering such motions that courts were able to review parts of the record which included the district attorney's comments and advisements, in addition to testimonial evidence. (See, e.g., People v. Snow (1977) 72 Cal. App. 3d 950, 958 [140 Cal. Rptr. 427] [record of hearing revealed district attorney advised grand jury of possible exculpatory evidence]; People v. Laney (1981) 115 Cal. App. 3d 508, 512-513 [171 Cal. Rptr. 493] [posttrial appeal challenging grand jury proceedings included record of district attorney's admonitions and dialogue with witnesses who did not testify]; People v. Coleman (1978) 84 Cal. App. 3d 1016, 1019 [149 Cal. Rptr. 134] [transcript contained district attorney's comments and answers to grand juror's questions at conclusion of testimonial evidence]; People v. Backus, supra, 23 Cal. 3d 360, 393 [grand jury advised of certain evidence admissible for a limited purpose]; Cummiskey v. Superior Court, supra, 3 Cal. 4th 1018, 1031-1032 [transcript of question and answer exchange between grand jurors and district attorney quoted].) Although there was, and still is, no express statute requiring or authorizing the transcription or production of nontestimonial portions of the grand jury proceedings, these cases reveal that courts have routinely allowed an indicted defendant to obtain records of the proceedings which were relevant to a statutory motion to dismiss. The last two above cited cases, People v. Backus, and Cummiskey v. Superior Court (hereafter Backus and Cummiskey), are binding on us as Supreme Court authority and thus bear closer examination.