In Brady v. Maryland (1963) 373 U.S. 83, the United States Supreme Court held "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." The high court later held the duty to disclose such evidence exists even when the accused has not requested it. (United States v. Agurs (1976) 427 U.S. 97, 107.) Further, the duty extends to evidence known to police investigators. (Kyles v. Whitley (1995) 514 U.S. 419, 438.) "In order to comply with Brady, therefore, 'the individual prosecutor has a duty to learn of any favorable evidence known to the others acting on the government's behalf in the case, including the police.'" (People v. Salazar (2005) 35 Cal.4th 1031, 1042 (Salazar).) Disclosure is only required if the evidence is "both favorable to the defendant and material on either guilt or punishment." (In re Sassounian, supra, 9 Cal.4th at p. 543.) "Evidence is 'favorable' if it either helps the defendant or hurts the prosecution, as by impeaching one of its witnesses." (Id. at p. 544.) "Evidence is 'material' 'only if there is a reasonable probability that, had it been disclosed to the defense, the result of the proceeding would have been different.'" (Ibid.; United States v. Bagley (1985) 473 U.S. 667, 682.) "The requisite 'reasonable probability' is a probability sufficient to 'undermine confidence in the outcome' on the part of the reviewing court. . It is a probability assessed by considering the evidence in question under the totality of the relevant circumstances and not in isolation or in the abstract." (In re Sassounian, supra, 9 Cal.4th at p. 544.) The showing of a mere possibility of a different outcome is insufficient. (Strickler v. Greene (1999) 527 U.S. 263, 291.) "'In general, impeachment evidence has been found to be material where the witness at issue "supplied the only evidence linking the defendant(s) to the crime," citations, or where the likely impact on the witness's credibility would have undermined a critical element of the prosecution's case . In contrast, a new trial is generally not required when the testimony of the witness is "corroborated by other testimony."'" (Salazar, supra, 35 Cal.4th at p. 1050.) "For purposes of analyzing materiality, we consider both the evidence submitted in support of the petition for writ of habeas corpus and the record of the trial." (In re Brown (1998) 17 Cal.4th 873, 888, fn. 8.) "'The reviewing court may consider directly any adverse effect that the prosecutor's failure to respond might have had on the preparation or presentation of the defendant's case.'" (Id. at p. 887, citing United States v. Bagley, supra, 473 U.S. at p. 683.) In the same vein, "in determining whether there is a reasonable probability that disclosure of the evidence would have yielded a different outcome under Brady, '"the court must consider the non-disclosure dynamically, taking into account the range of predictable impacts on trial strategy."'" (People v. Gaines (2009) 46 Cal.4th 172, 184.) "Under the due process clause of the Fourteenth Amendment to the United States Constitution, a prisoner may seek relief in habeas corpus on the ground that the prosecution did not disclose evidence." (In re Sassounian, supra, 9 Cal.4th at p. 543.) The petitioner bears the burden of proving his or her claim by a preponderance of the evidence. (Id. at pp. 546-547.) In Salazar, supra, 35 Cal.4th 1031, the California Supreme Court addressed the standard of review applicable to a Brady claim as follows: "Conclusions of law or of mixed questions of law and fact, such as the elements of a Brady claim Citation, are subject to independent review. . Because the trial court can observe the demeanor of the witnesses and their manner of testifying, findings of fact, though not binding, are entitled to great weight when supported by substantial evidence." (Id. at p. 1042, italics added; People v. Letner and Tobin (2010) 50 Cal.4th 99, 176.)