Opinion
CLARK, J.Petitioner seeks writ of prohibition restraining respondent superior court from proceeding to trial by indictment charging him with conspiracy to commit and with commission of the crime of illegally transporting and selling a controlled substance (amphetamine tablets). (Pen. Code, § 182; Health & Saf. Code, § 11352.)
Prior to submission of the matter to the grand jury, petitioner’s testimony at a preliminary hearing led the magistrate to dismiss a complaint charging him with the same offenses. The district attorney did not bring this testimony to the attention of the grand jury.
The reception and consideration of exculpatory evidence by the grand jury is governed by section 939.7 of the Penal Code. “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.”
*251Petitioner’s testimony at the preliminary hearing did tend to “explain away” the charges against him, at least in the magistrate’s opinion. Therefore, petitioner contends, the district attorney had an implied duty under section 939.7 to disclose this testimony to the grand jury. The People respond that the district attorney is not obligated to present exculpatory evidence to the grand juiy unless the jury calls for it.
The People’s response is disingenuous. The grand jury cannot be expected to call for evidence of which it is kept ignorant. When a district attorney seeking an indictment is aware of evidence reasonably tending to negate guilt, he is obligated under section 939.7 to inform the grand jury of its nature and existence. Such information having been withheld here, the writ of prohibition must issue.
The Preliminary Hearing
(a) Prosecution Testimony
On 31 July 1973, petitioner agreed to sell 200,000 amphetamine tablets to Mr. Logan, a federal undercover narcotics agent, and Mr. Young, Logan’s informant. Petitioner told them the transaction would be consummated through Mr. Sherman because a pending court appearance caused petitioner concern. On three occasions in the preceding five weeks, agent Young had observed petitioner and Sherman in Mexico, negotiating to purchase amphetamine tablets.
On the evening of 7 August 1973, the transaction having been postponed once, Sherman telephoned Logan and Young in their hotel room in Stockton, arranging to meet them there. Twenty minutes later, petitioner drove up to Sherman’s house in Lodi and Sherman came out to the car where, they talked for five minutes. They then drove to Stockton in separate cars, petitioner leading the way. Sherman went to Logan and Young’s room while petitioner circled the vicinity of the hotel for 15 to 20 minutes, finally parking within 200 yards of Sherman’s car.
Sherman offered to sell Logan 50,000 amphetamine tablets for $3,000. Objecting that his agreement had been with petitioner, Logan told Sherman he wanted to know with whom he was dealing. Sherman replied that petitioner did not want to be directly involved because he had a prior conviction. When Logan pressed Sherman as to the ownership of the tablets, he replied, “They’re borrowed but don’t worry. *252Me and Ray are partners.” When the transaction was completed petitioner and Sherman were arrested.
(b) Petitioner’s Testimony
In March 1973, petitioner was charged with one count of selling restricted dangerous drugs and two counts of possessing such drugs for sale. At a pretrial conference in superior court, petitioner was informed that the district attorney would recommend a county jail sentence in return for cooperation in securing information concerning other narcotics dealers. Petitioner agreed and was told to work with Deputy District Attorney Saiers. When petitioner subsequently balked at appearing as a witness in prosecutions resulting from information he was to supply, Mr. Saiers warned him that he would go to prison unless he cooperated. Pursuant to a bargain struck with Mr. Saiers just before his court appearance on 6 August 1973, petitioner was permitted to plead guilty to one of the possession counts, the other two counts were dismissed, and the probation and sentence hearing was continued until 17 September 1973, to give petitioner more time to “produce.”
Petitioner had never been in Mexico with Sherman. He did agree to sell amphetamine tablets to Young and Logan when they met on 31 July 1973, but did so with the intention of informing on them. He did not tell them the transaction would be consummated through Sherman. Petitioner had nothing to do with the transaction on 7 August 1973; he was in the area because he hoped to inform on Sherman.
(c) Dismissal
The magistrate’s role is limited by statute to determining whether or not there is sufficient cause to believe the defendant guilty of a public offense. (See Pen. Code, §§ 871, 872.) Within the framework of his limited role, however, the magistrate may weigh the evidence, resolve conflicts, and give or withhold credence to particular witnesses. (People v. Uhlemann (1973) 9 Cal.3d 662, 667 [108 Cal.Rptr. 657, 511 P.2d 609]; Jones v. Superior Court (1971) 4 Cal.3d 660, 667 [94 Cal.Rptr. 289, 483 P.2d 1241].) In dismissing the charges against petitioner, the magistrate —possibly influenced by the People’s failure to call Deputy District Attorney Saiers, or anyone else, to rebut petitioner’s testimony—resolved the conflicts in the evidence against the People.
*253 The Grand Jury Hearing
The People have chosen a poor vehicle for arguing that the district attorney is not obligated to present exculpatory evidence to the grand jury unless the jury calls for it. Not only did the district attorney fail to inform the grand jury of petitioner’s preliminary hearing testimony, but he also created the false impression that petitioner would refuse to testify if called. At the conclusion of the grand jury hearing, after three other witnesses had testified in the interim, the district attorney recalled the arresting officer and elicited his testimony that, following arrest and advisement of his Miranda rights, petitioner had refused to make a statement upon the advice of counsel. Reference to petitioner’s invocation of the privilege against self-incrimination was clear misconduct, as the Attorney General concedes. (People v. Miller (1966) 245 Cal.App.2d 112, 156 [53 Cal.Rptr. 720], disapproved on another ground in People v. Doherty (1967) 67 Cal.2d 9, 14-15 [59 Cal.Rptr. 857, 429 P.2d 177]; see Griffin v. California (1965) 380 U.S. 609 [14 L.Ed.2d 106, 85 S.Ct. 1229]; People v. Modesto (1967) 66 Cal.2d 695, 710-711 [59 Cal.Rptr. 124, 427 P.2d 788].) But more importantly, the grand jury’s power to order the production of evidence which may “explain away” the charges under consideration was thereby thwarted.
The Protective Role of the Grand Jury
“Under the ancient English system .... the most valuable function of the grand jury was not only to examine into the commission of crimes, but to stand between the prosecutor and the accused, and to determine whether the charge was founded upon credible testimony or was dictated by malice or personal ill will.” (Hale v. Henkel (1906) 201 U.S. 43, 59 [50 L.Ed. 652, 659, 26 S.Ct. 370], quoted in Hoffman v. United States (1951) 341 U.S. 479, 485 [95 L.Ed. 1118, 1123, 71 S.Ct. 814].)
The Fifth Amendment guarantee that a civilian may not be held to answer in a federal prosecution for a capital or otherwise infamous crime “ ‘unless on a presentment or indictment of a Grand Jury’ ” presupposes a grand jury “ ‘acting independently of either prosecuting attorney or judge,’ whose mission is to clear the innocent, no less than to bring to trial those who may be guilty.” (United States v. Dionisio (1973) 410 U.S. 1, 16-17 [35 L.Ed.2d 67, 81, 93 S.Ct. 764]; citation omitted.)
The grand jury’s “historic role as a protective bulwark standing solidly between the ordinary citizen and an overzealous prosecutor” (United *254States v. Dionisio, supra, at p. 17 [35 L.Ed.2d at p. 81]) is as well-established in California as it is in the federal system. “If [exculpatory] evidence exists, and [the grand jury] have reason to believe that it is within their reach, they may request it to be produced, and for that purpose may order the district attorney to issue process for the witnesses ([former] § 920, Pen. Code), to the end that the citizen may be protected from the trouble, expense, and disgrace of being arraigned and tried in public on a criminal charge for which there is no sufficient cause. A grand jury should néver forget that it sits as the great inquest between the State and the citizen, to make accusations only upon sufficient evidence of guilt, and to protect the citizen against unfounded accusation, whether from the government, from partisan passion, or private malice.” (In re Tyler (1884) 64 Cal. 434, 437 [1 P. 884].)
The protective role traditionally played by the grand jury is reinforced in California by statute. The forerunner of section 939.7 was former section 920 of the Penal Code, the section cited in In re Tyler, supra. Section 920 provided; “The grand jury is not bound to hear evidence for the defendant; but it is their duty to weigh all the evidence submitted to them, and when they have reason to believe that other evidence within their reach will explain away the charge, they should order such evidence to be produced, and for that purpose may require the district attorney to issue process for the witnesses.” (Enacted by Stats. 1871-1872, ch. 288, § 1, p. 391; repealed by Stats. 1959, ch. 501, § 1, p. 2443.) Section 920, in turn, was a word-for-word reenactment of a statute passed by the first session of our Legislature. (Stats. 1850, ch. 119, § 232, p. 292.)
The People contend the proper construction of section 939.7 is that “the impetus for the presentation of exculpatory evidence must originate in the grand jury, not the district attorney.” However, unless so informed by the district attorney, the grand juiy ordinarily has no “reason to believe that other evidence within its reach will explain away the charge.” The defendant is not entitled to appear before the grand jury in person (People v. Foster (1926) 198 Cal. 112, 120 [243 P. 667]) or by counsel (People v. Dale (1947) 79 Cal.App.2d 370, 376 [179 P.2d 870]). The defendant’s right to bring exculpatory evidence to the attention of the grand jury by letter (In re Tyler, supra, 64 Cal. at p. 437) is illusory unless he knows his case will be under consideration by them. Because the proceedings of the grand jury are held in secret without notice to the defendant, the construction of section 939.7 urged by the People would nullify its protective role. (See Witkin, Cal. Criminal Procedure, p. 167.)
*255 The District Attorney’s Duty
“The duty of the district attorney is not merely that of an advocate. His duty is not to obtain convictions, but to fully and fairly present to the court the evidence material to the charge upon which the defendant stands trial. . . .” (In re Ferguson (1971) 5 Cal.3d 525, 531 [96 Cal.Rptr. 594, 487 P.2d 1234].) At trial—where the adversary system operates—the district attorney may discharge his duty by disclosing to the defendant the substantial material evidence favorable to him. (People v. Ruthford (1975) 14 Cal.3d 399 [121 Cal.Rptr. 261, 534 P.2d 1341].) The district attorney is not obligated to present such evidence at trial himself because it is defense counsel’s duty to do so. (See People v. Kiihoa (1960) 53 Cal.2d 748, 752 [3 Cal.Rptr. 1, 349 P.2d 673].)
However, the adversary system does not extend to grand jury proceedings. As has been explained, if the district attorney does not bring exculpatory evidence to the attention of the grand jury, the jury is unlikely to learn of it. We hold, therefore, that when a district attorney seeking an indictment is aware of evidence reasonably tending to negate guilt, he is 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. Having disposed of this case on statutory grounds, we need not consider petitioner’s alternative due process argument. We have considered the People’s procedural objections and find them meritless.
The writ issues without prejudice to the district attorney’s continuing tó prosecute these charges by seeking another indictment, or by filing another complaint. (See People v. Uhlemann (1973) 9 Cal.3d 662, 666 [108 Cal.Rptr. 657, 511 P.2d 609].)
McComb, J., Tobriner, J., Sullivan, J., and Burke, J.,* concurred.
Retired Associate Justice of the Supreme Court sitting under assignment by the Chairman of the Judicial Council.