Prosecutors have a constitutional mandate to disclose exculpatory material evidence to defendants in criminal cases. "The suppression by the prosecution of evidence favorable to an accused upon request violates due process where the evidence is material either to guilt or to punishment, irrespective of the good faith or bad faith of the prosecution." (Brady v. Maryland (1963) 373 U.S. 83, 87 83 S. Ct. 1194, 1196-1197, 10 L. Ed. 2d 215 (Brady).) In United States v. Agurs (1976) 427 U.S. 97, 107 96 S. Ct. 2392, 2399, 49 L. Ed. 2d 342, the Brady rule was extended to impose a duty on prosecutors to volunteer exculpatory matter to the defense even without a request for such material. (Accord, In re Ferguson (1971) 5 Cal. 3d 525, 532-533 96 Cal. Rptr. 594, 487 P.2d 1234.) The prosecution has a duty to disclose exculpatory evidence to the defense. Brady exculpatory evidence is the only substantive discovery mandated by the United States Constitution. a criminal defendant does not have a general constitutional right to discovery. (Weatherford v. Bursey (1977) 429 U.S. 545, 559 97 S. Ct. 837, 845, 51 L. Ed. 2d 30; Gray v. Netherland (1996) 518 U.S. 152, 168 116 S. Ct. 2074, 2083-2084, 135 L. Ed. 2d 457; accord, People v. Gonzalez (1990) 51 Cal. 3d 1179, 1258 275 Cal. Rptr. 729, 800 P.2d 1159.) The constitutional duty that requires prosecutors to disclose exculpatory evidence to a criminal defendant is independent from the statutory duty contained in section 1054.1, subdivision (e). (Izazaga v. Superior Court, supra, 54 Cal. 3d at p. 378; 1054, subd. (e).) "The prosecutor's duties of disclosure under the due process clause are wholly independent of any statutory scheme of reciprocal discovery. the due process requirements are self-executing and need no statutory support to be effective. . . . If a statutory discovery scheme exists, these due process requirements operate outside such a scheme. the prosecutor is obligated to disclose such evidence voluntarily, whether or not the defendant makes a request for discovery. "The new discovery chapter contemplates disclosure outside the statutory scheme pursuant to constitutional requirements as enunciated in Brady, supra, 373 U.S. 83 and its progeny." (Izazaga v. Superior Court, supra, 54 Cal. 3d at p. 378, original italics.) A prosecutor's duty under Brady to disclose material exculpatory evidence extends to evidence the prosecutor--or the prosecution team-- knowingly possesses or has the right to possess. The prosecution team includes both investigative and prosecutorial agencies and personnel. (See In re Brown (1998) 17 Cal. 4th 873, 879 72 Cal. Rptr. 2d 698, 952 P.2d 715.) What would happen if disclose exculpatory evidence was not within the duty of the prosecutor ? In Kyles v. Whitley (1995) 514 U.S. 419, 437-438 115 S. Ct. 1555, 1567, 131 L. Ed. 2d 490, the Supreme Court held that a prosecutor has a duty to learn of favorable evidence known to other prosecutorial and investigative agencies acting on the prosecution's behalf, including police agencies. The scope of the prosecutorial duty to disclose encompasses exculpatory evidence possessed by investigative agencies to which the prosecutor has reasonable access. (People v. Robinson (1995) 31 Cal. App. 4th 494, 499 37 Cal. Rptr. 2d 183.) A prosecutor has a duty to search for and disclose exculpatory evidence if the evidence is possessed by a person or agency that has been used by the prosecutor or the investigating agency to assist the prosecution or the investigating agency in its work. The important determinant is whether the person or agency has been "acting on the government's behalf" (Kyles v. Whitley, supra, 514 U.S. at p. 437 115 S. Ct. at p. 1567) or "assisting the government's case." (In re Brown, supra, 17 Cal. 4th at p. 881.)