OPINION ON APPELLANT’S PETITION FOR DISCRETIONARY REVIEW
A jury convicted appellant and his co-defendant, Ricky James Davis, of murder pursuant to Tex.Penal Code Ann. § 19.-02(a)(1). The trial judge assessed appellant’s punishment at confinement for life. Tex.Penal Code Ann. § 12.42(c). The Court of Appeals affirmed. Davis and Thomas v. State, Nos. 05-89-00496-CR and 05-89-00497-CR, Delivered October 31,1990 (Tex. App. — Dallas 1990) (not published). We granted appellant’s petition for discretionary review to determine whether the Court of Appeals erred in not ordering a new trial when the State failed to disclose exculpatory evidence in violation of the Due Process *401 Clauses of the Fourteenth Amendment and Art. I, § 19 of the Texas Constitution. 1
I.
Appellant, Davis, Charles Sims and James Walker arrived at Jeannie Sims’ apartment. Some time later, the deceased arrived with Denise Crowder. At trial, Jeannie Sims, the deceased’s former girlfriend, and Crowder, the deceased’s fiancee, each testified they saw appellant drag the deceased behind the apartment building and shoot him. Police officers interviewed Walker several days after the alleged offense. Approximately one month later, Walker was interviewed by Dallas County Assistant District Attorney, Suzanne Lom-enick, and her investigator, Yolanda Moses. On the first day of the trial, Lomenick and Walker met in the courtroom and again discussed the case.
Prior to trial, Davis filed a motion for the disclosure of favorable evidence. At the hearing on the motion the trial judge asked Lomenick if she had any evidence favorable to either appellant or Davis. Lomenick denied having any favorable evidence. 2 At trial, the State relied exclusively on the testimony of Jeannie Sims and Crowder to implicate appellant in the murder. 3 Walker did not testify at either phase of appellant’s trial. Appellant filed a motion for new trial, in part, contending:
... Exculpatory evidence tending to establish the innocence of the accused has been intentionally withheld or not revealed by the prosecutor or his agents prior to trial. This evidence is the exculpatory evidence that could be provided by James Walker.
At the hearing on appellant’s motion for new trial, Walker testified that appellant was in the front yard of the apartment building when Walker went upstairs to watch a movie. While upstairs Walker heard loud voices but could not tell who was arguing. Walker then heard shots from behind the apartment building. Walker fell to the floor, got up and “within a matter of ... five seconds” ran downstairs. When Walker reached the front porch of the apartment, he saw appellant standing in the front yard. Walker and Charles Sims ran behind the apartment building where they saw Davis standing next to the deceased. Davis pointed a gun at Walker and Charles Sims, who ran back inside the apartment. Walker stated appellant could not have moved from the back of the apartment building to the front yard within the few seconds it took Walker to run downstairs and outside the apartment building.
It is undisputed that Walker told this version of the events to police officers once, and to Lomenick twice. At the hearing on the motion for a new trial, Lomenick testified she did not inform defense counsel or the trial judge of the information she learned from Walker. Lomenick did not deny Walker’s version of the events. At the conclusion of the motion hearing, Lom-enick stated, “I would have brought [Walker’s testimony] to the court’s attention had I thought it would ... be exculpatory in any manner.” The trial judge overruled appellant’s motion for new trial.
The Court of Appeals acknowledged Walker’s testimony was exculpatory but
*402
held appellant failed to show enough harm to warrant reversal. Slip op. pg. 12. Relying upon
United States v. Agurs,
II.
In order to address appellant’s grounds for review, we must first review the history of the State’s duty to disclose favorable evidence. The State’s duty to disclose evidence favorable to the defendant is an extension of
Mooney v. Holohan,
In
Brady v. Maryland,
... not punishment of society for the misdeeds of a prosecutor but avoidance of an unfair trial to the accused. Society wins not only when the guilty are convicted but when criminal trials are fair; our system of the administration of justice suffers when any accused is treated unfairly.
Brady,
Brady was charged with first degree murder, a capital offense. At his trial, Brady admitted participating in the crime but claimed his co-defendant committed the murder. Prior to trial, Brady requested disclosure of the co-defendant’s extrajudicial statements. The prosecution made several of the statements available but withheld the statement in which the co-defendant admitted the actual homicide. The Supreme Court held the suppression of the co-defendant’s confession was a violation of the Due Process Clause of the Fourteenth Amendment. Specifically, the Court held, “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 or bad faith of the prosecution.”
Brady,
The Supreme Court, in
Moore v. Illinois,
In
United States v. Agurs,
Second, in the case of a specific request, the Court noted:
... Although there is, of course no duty to provide defense counsel with unlimited discovery of everything known by the prosecutor, if the subject matter of such a request is material, or indeed if a substantial basis for claiming materiality exists, it is reasonable to require the prosecutor to respond either by furnishing the information or by submitting the problem to the trial judge. When the prosecutor receives a specific and relevant request, the failure to make any response is seldom, if ever, excusable.
Agurs,
Finally, when there was no request or only a general request, a “reasonable doubt” standard applied because a finding of guilt is permitted only when supported by “evidence establishing guilt beyond a reasonable doubt. It necessarily follows that if the omitted evidence create[d] a reasonable doubt that did not otherwise exist, constitutional error has been committed.”
6
Agurs,
In
United States v. Bagley,
The
Bagley
Court eliminated the request prong
of Brady
and revised the three standards of materiality in
Agurs
to two standards. First, in situations of the knowing use of perjured testimony the Court retained the harmless error standard.
Bagley,
We find the Strickland [v. Washington,466 U.S. 668 ,104 S.Ct. 2052 ,80 L.Ed.2d 674 (1984)] formulation of the Agurs test for materiality sufficiently *404 flexible to cover ‘no request,’ ‘general request,’ and ‘specific request’ cases of prosecutorial failure to disclose evidence favorable to the accused: The evidence is material only if there is a reasonable probability that, had the evidence been disclosed to the defense, the result of the proceeding, would have been different. A ‘reasonable probability’ is a probability sufficient to undermine confidence in the outcome.
Bagley,
Consequently, the Due Process Clause of the Fourteenth Amendment is violated when a prosecutor fails to disclose evidence which is favorable to the accused that creates a probability sufficient to undermine the confidence in the outcome of the proceeding.
III.
The Court of Appeals, relying on
Agurs,
concluded the evidence did not create a
reasonable doubt
as to appellant’s guilt. As can be seen from the foregoing analysis, the Court of Appeals applied the wrong standard of materiality. Under
Bagley
the reasonable probability standard,
not
the reasonable doubt standard, is to be used to determine materiality.
Bagley,
As previously noted, a three part test is used to determine when a prosecutor has violated the Due Process Clause of the Fourteenth Amendment. Such a violation occurs when a prosecutor 1) fails to disclose evidence 2) which is favorable to the accused 3) that creates a probability sufficient to undermine the confidence in the outcome of the proceeding. We must first determine whether the prosecutor failed to disclose Walker’s testimony. The record indicates that Walker was questioned by the police several days after the alleged offense, and interviewed by Lomenick twice, the last time in the courtroom on the first day of trial. The State did not deny or refute the content of Walker’s testimony during the hearing on appellant’s motion for new trial. Clearly, the first part of the test has been met because the State knew of Walker’s testimony and failed to disclose the content of Walker’s testimony to appellant.
We must next determine whether the evidence was favorable. Favorable evidence is any evidence that “if disclosed and used effectively, it
may
make the difference between conviction and acquittal.”
Bagley,
The third part of the test requires us to determine whether Walker’s testimony was material, i.e., created a probability sufficient to undermine the confidence in the outcome of the proceeding. To make this determination we must examine the alleged error in the context of the entire record.
Bagley,
If ... one of only two eyewitnesses to a crime had told the prosecutor that the defendant was definitely not its perpetrator and if this statement was not disclosed to the defense, no court would hesitate to reverse a conviction resting on the testimony of the other eyewitness. But if there were fifty eyewitnesses, forty-nine of whom identified the defendant, and the prosecutor neglected to reveal that the other, who was without his badly needed glasses on the misty evening of the crime, had said that the criminal looked something like the defendant but couldn’t be sure as he had only had a brief glimpse, the result might well be different.
Id.,
Finally, “the reviewing court may consider directly any adverse effect that the prosecutor’s [nondisclosure] might have had on the preparation or presentation of the defendant’s case. The reviewing court should assess the possibility that such effect might have occurred in light of the totality of the circumstances and with an awareness of the difficulty of reconstructing in a post-trial proceeding the course that the defense and the trial would have taken had the defense not been misled by the prosecutor’s [failure to disclose].”
Bagley,
With the foregoing in mind, we note the State relied exclusively upon the testimony of Jeannie Sims and Denise Crowder to implicate appellant in the murder; no other evidence linked appellant to the alleged offense. The State’s case, therefore, rested upon the credibility of only two witnesses. It follows that evidence tending to exculpate appellant or impeach their testimony would have undermined the State’s case.
See, Bowen v. Maynard,
Walker’s testimony is exculpatory. As previously noted, Walker testified to seeing appellant in front of the apartment building. The shooting occurred behind the building. According to Walker, appellant could not have moved from the back of the apartment building to the front yard within the few seconds it took Walker to run downstairs and outside the apartment building. Therefore, Walker’s testimony exculpates appellant; appellant could not have committed the murder because he was in front of the apartment building at the time of the shooting. Accordingly, Walker’s exculpatory testimony was material in that it created a probability sufficient to undermine confidence in the verdict. 8
Additionally, Walker’s testimony impeaches the testimony of Jeannie Sims and Crowder. Jeannie Sims testified she saw appellant shoot the decedent once and then heard more shots after she went to the front of the apartment building. However, Walker testified that Jeannie Sims was watching a movie upstairs in the apartment when the shooting occurred and followed *406 Walker and Charlie Sims downstairs when the shooting ceased.
Walker further testified that, after running downstairs, he saw appellant in the front yard of the apartment building arguing with a woman seated in a car. Although not clear from the record, the woman seated in the car appears to be Crowder, who remained in the car after her arrival. However, Crowder testified she was in the back of the apartment building and saw appellant shoot the deceased. Further, Crowder testified that immediately after the incident, appellant allegedly forced her into a car in back of the apartment building.
Walker’s testimony as to the locations of Jeannie Sims and Crowder clearly impeaches their claims of having seen the shooting. Jeannie Sims could not have both witnessed the first shot and been upstairs during the shooting. Likewise, Crowder testified that she was behind the apartment building during the alleged offense and then was subject to an attempted abduction. However, Walker’s testimony places both appellant and Crowder in the front of the apartment building immediately after the shooting.
Accordingly, had Walker’s testimony been disclosed, appellant, could have used the testimony to controvert that of Jeannie Sims and Crowder.
See, Fairman,
Furthermore, the materiality of Walker’s impeachment testimony is especially compelling when we consider the overall strength of the State’s case. The inconsistencies between the testimony of Jeannie Sims and Crowder weakened the State’s case. Jeannie Sims testified that she saw appellant drag the deceased off the front porch and, along with Davis, pistol whip the deceased while dragging him up the driveway towards the back of the apartment building. However, Crowder testified that immediately after the deceased was pulled off the porch, appellant approached her while she sat in the deceased’s car. Crowder did not see anyone drag the deceased up the driveway, and Jeannie Sims did not mention that appellant approached Crowder after dragging and beating the deceased.
Also, while both Jeannie Sims and Crow-der testified to having seen appellant shoot the deceased, neither mentions the other being present. 10 On direct examination, Jeannie Sims indicated that she was by the back corner of the apartment building when appellant allegedly fired the first shot. Crowder testified that she also was standing by the back corner of the apartment building when the first shot was fired but saw only appellant, Davis and the deceased. At no time did Crowder mention seeing Jeannie Sims. Therefore, Crowder’s testimony contradicts that of Jeannie Sims and Walker's impeachment testimony would have cast further doubt on the credibility of one or both of these witnesses.
Finally, the State’s failure to disclose Walker’s testimony adversely affected the preparation and presentation of appellant’s case. By failing to disclose Walker’s
exculpatory
testimony, the State prevented appellant from effectively mounting a de
*407
fense,
Lindsey,
Therefore, Walker's exculpatory testimony was material, as was his impeachment testimony, because his testimony created a probability sufficient to undermine confidence in the outcome of appellant’s trial. Accordingly, the third part of the test has been met.
For these reasons, we hold the Due Process Clause of the Fourteenth Amendment was violated when the State failed to disclose Walker’s testimony. 11
IV.
The State has an affirmative duty to disclose evidence favorable and material to a defendant’s guilt or punishment under the Due Process Clause of the Fourteenth Amendment.
Brady,
The judgments of the Court of Appeals and the trial court are reversed and this case is remanded to the trial court.
Notes
.Specifically, appellant’s grounds for review state:
Point of Error [sic] I:
The Court of appeals and the trial court erred in refusing to grant Appellant a new trial based on the prosecutor withholding exculpatory evidence under the due process clause of the U.S. Constitution, Amendments V and XIV.
Point of Error [sic] II:
The Court of Appeals and the trial court erred in refusing to grant Appellant a new trial based on the prosecutor withholding exculpatory evidence under the due process clause of the Texas Constitution, Article I, Section 19.
. At the hearing the following occurred:
THE COURT: The Motion for discovery or disclosure of evidence favorable to the accused. Ms. Lomenick, do you have any evidence favorable to the accused?
MS. LOMENICK: No, I do not judge.
THE COURT: Favorable to either of the accused?
MS. LOMENICK: In either case, I do not.
. The record indicates that Charles Sims had died by the time of trial.
. Unless otherwise indicated, all emphasis herein is supplied by the author.
. Because
Brady
was aimed at ensuring that an accused receives a fair trial rather than punishing the prosecutor for failing to disclose favorable evidence, the prosecution's obligation to disclose is not measured by the moral culpability, or the willfulness, of the prosecutor.
Agurs,
. The Court described a constitutional violation as follows:
Unless the omission deprived the defendant of a fair trial, there was no constitutional violation requiring that the verdict be set aside;
and absent a constitutional violation, there was no breach of the prosecutor's constitutional duty to disclose.
Agurs,
. Appellant contends the harmless error standard of Tex.R.App.P. 81(b)(2) should apply. However, the reasonable probability standard is
not
the same as Rule 81(b)(2). As its name suggests, the reasonable probability standard requires a determination of the
probability
the withheld evidence would have had on the outcome. Additionally, the burden rests with the defendant to prove the error.
Strickland,
. Although Walker's testimony tends to exonerate appellant,
Brady
does not require the exculpatory evidence be certain to exonerate, only that it
may
do so if used effectively.
See, Bagley,
. Assuming arguendo Walker’s testimony would not have been sufficient to controvert the testimony of both Jeannie Sims
and
Crowder, his testimony would nevertheless be material because it could have raised doubts as to the credibility of one of the witnesses. As the Fifth Circuit stated in
Lindsey:
“[OJur experience at the bar has been that positive identification by two unshaken witnesses possesses many times the power of such an identification by one only, and that
the destruction by cross-examination of the credibility of one of two crucial
witnesses—
even if the other remains untouched
— may
have consequences for the case extending far beyond the discrediting of his own testimony.
”
Lindsey,
. Although the record is unclear as to their distance and exact location, Jeannie Sims’ and Crowder’s testimony suggests that both were around the rear corner of the apartment build,ing between 10 to 20 feet from the shooting.
. Having determined the Due Process Clause of the Fourteenth Amendment was violated, we need not address appellant’s second ground for review.
